diff --git a/plutus-core/plutus-core.cabal b/plutus-core/plutus-core.cabal
index 884ddce8a29..c94233a91e8 100644
--- a/plutus-core/plutus-core.cabal
+++ b/plutus-core/plutus-core.cabal
@@ -200,6 +200,7 @@ library
         Language.UntypedPlutusCore.Core.Instance.Pretty.Readable
         Language.UntypedPlutusCore.Core.Instance.CBOR
         Language.UntypedPlutusCore.Core.Type
+        Language.UntypedPlutusCore.Core.Plated
         Language.UntypedPlutusCore.Size
         Language.UntypedPlutusCore.Subst
 
diff --git a/plutus-core/src/Language/PlutusCore/CBOR.hs b/plutus-core/src/Language/PlutusCore/CBOR.hs
index 1a3d31fcfb5..13a919814d2 100644
--- a/plutus-core/src/Language/PlutusCore/CBOR.hs
+++ b/plutus-core/src/Language/PlutusCore/CBOR.hs
@@ -273,8 +273,8 @@ instance Serialise Special
 deriving newtype instance Serialise Index
 
 instance Serialise DeBruijn where
-    encode (DeBruijn txt i) = encode txt <> encode i
-    decode = DeBruijn <$> decode <*> decode
+    encode (DeBruijn i) = encode i
+    decode = DeBruijn <$> decode
 
 instance Serialise TyDeBruijn where
     encode (TyDeBruijn n) = encode n
diff --git a/plutus-core/src/Language/PlutusCore/Core/Type.hs b/plutus-core/src/Language/PlutusCore/Core/Type.hs
index 011759cf29c..f585507b1e2 100644
--- a/plutus-core/src/Language/PlutusCore/Core/Type.hs
+++ b/plutus-core/src/Language/PlutusCore/Core/Type.hs
@@ -2,6 +2,7 @@
 {-# LANGUAGE DeriveAnyClass        #-}
 {-# LANGUAGE DerivingVia           #-}
 {-# LANGUAGE FlexibleInstances     #-}
+{-# LANGUAGE LambdaCase            #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE TypeFamilies          #-}
 {-# LANGUAGE UndecidableInstances  #-}
diff --git a/plutus-core/src/Language/PlutusCore/DeBruijn.hs b/plutus-core/src/Language/PlutusCore/DeBruijn.hs
index fce33d6c941..89b82bad762 100644
--- a/plutus-core/src/Language/PlutusCore/DeBruijn.hs
+++ b/plutus-core/src/Language/PlutusCore/DeBruijn.hs
@@ -15,6 +15,8 @@ module Language.PlutusCore.DeBruijn
     , unDeBruijnTy
     , unDeBruijnTerm
     , unDeBruijnProgram
+    , unNameDeBruijn
+    , unNameTyDeBruijn
     ) where
 
 import           Language.PlutusCore.DeBruijn.Internal
@@ -28,22 +30,22 @@ import           Control.Monad.Reader
 
 import qualified Data.Bimap                            as BM
 
--- | Convert a 'Type' with 'TyName's into a 'Type' with 'TyDeBruijn's.
+-- | Convert a 'Type' with 'TyName's into a 'Type' with 'NamedTyDeBruijn's.
 deBruijnTy
     :: MonadError FreeVariableError m
-    => Type TyName uni ann -> m (Type TyDeBruijn uni ann)
+    => Type TyName uni ann -> m (Type NamedTyDeBruijn uni ann)
 deBruijnTy = flip runReaderT (Levels 0 BM.empty) . deBruijnTyM
 
--- | Convert a 'Term' with 'TyName's and 'Name's into a 'Term' with 'TyDeBruijn's and 'DeBruijn's.
+-- | Convert a 'Term' with 'TyName's and 'Name's into a 'Term' with 'NamedTyDeBruijn's and 'NamedDeBruijn's.
 deBruijnTerm
     :: MonadError FreeVariableError m
-    => Term TyName Name uni ann -> m (Term TyDeBruijn DeBruijn uni ann)
+    => Term TyName Name uni ann -> m (Term NamedTyDeBruijn NamedDeBruijn uni ann)
 deBruijnTerm = flip runReaderT (Levels 0 BM.empty) . deBruijnTermM
 
--- | Convert a 'Program' with 'TyName's and 'Name's into a 'Program' with 'TyDeBruijn's and 'DeBruijn's.
+-- | Convert a 'Program' with 'TyName's and 'Name's into a 'Program' with 'NamedTyDeBruijn's and 'NamedDeBruijn's.
 deBruijnProgram
     :: MonadError FreeVariableError m
-    => Program TyName Name uni ann -> m (Program TyDeBruijn DeBruijn uni ann)
+    => Program TyName Name uni ann -> m (Program NamedTyDeBruijn NamedDeBruijn uni ann)
 deBruijnProgram (Program ann ver term) = Program ann ver <$> deBruijnTerm term
 
 {- Note [De Bruijn conversion and recursion schemes]
@@ -54,7 +56,7 @@ These are normally constant in a catamorphic application.
 deBruijnTyM
     :: (MonadReader Levels m, MonadError FreeVariableError m)
     => Type TyName uni ann
-    -> m (Type TyDeBruijn uni ann)
+    -> m (Type NamedTyDeBruijn uni ann)
 deBruijnTyM = \case
     -- variable case
     TyVar ann n -> TyVar ann <$> tyNameToDeBruijn n
@@ -75,7 +77,7 @@ deBruijnTyM = \case
 deBruijnTermM
     :: (MonadReader Levels m, MonadError FreeVariableError m)
     => Term TyName Name uni ann
-    -> m (Term TyDeBruijn DeBruijn uni ann)
+    -> m (Term NamedTyDeBruijn NamedDeBruijn uni ann)
 deBruijnTermM = \case
     -- variable case
     Var ann n -> Var ann <$> nameToDeBruijn n
@@ -96,27 +98,27 @@ deBruijnTermM = \case
     Constant ann con -> pure $ Constant ann con
     Builtin ann bn -> pure $ Builtin ann bn
 
--- | Convert a 'Type' with 'TyDeBruijn's into a 'Type' with 'TyName's.
+-- | Convert a 'Type' with 'NamedTyDeBruijn's into a 'Type' with 'TyName's.
 unDeBruijnTy
     :: (MonadQuote m, MonadError FreeVariableError m)
-    => Type TyDeBruijn uni ann -> m (Type TyName uni ann)
+    => Type NamedTyDeBruijn uni ann -> m (Type TyName uni ann)
 unDeBruijnTy = flip runReaderT (Levels 0 BM.empty) . unDeBruijnTyM
 
--- | Convert a 'Term' with 'TyDeBruijn's and 'DeBruijn's into a 'Term' with 'TyName's and 'Name's.
+-- | Convert a 'Term' with 'NamedTyDeBruijn's and 'NamedDeBruijn's into a 'Term' with 'TyName's and 'Name's.
 unDeBruijnTerm
     :: (MonadQuote m, MonadError FreeVariableError m)
-    => Term TyDeBruijn DeBruijn uni ann -> m (Term TyName Name uni ann)
+    => Term NamedTyDeBruijn NamedDeBruijn uni ann -> m (Term TyName Name uni ann)
 unDeBruijnTerm = flip runReaderT (Levels 0 BM.empty) . unDeBruijnTermM
 
--- | Convert a 'Program' with 'TyDeBruijn's and 'DeBruijn's into a 'Program' with 'TyName's and 'Name's.
+-- | Convert a 'Program' with 'NamedTyDeBruijn's and 'NamedDeBruijn's into a 'Program' with 'TyName's and 'Name's.
 unDeBruijnProgram
     :: (MonadQuote m, MonadError FreeVariableError m)
-    => Program TyDeBruijn DeBruijn uni ann -> m (Program TyName Name uni ann)
+    => Program NamedTyDeBruijn NamedDeBruijn uni ann -> m (Program TyName Name uni ann)
 unDeBruijnProgram (Program ann ver term) = Program ann ver <$> unDeBruijnTerm term
 
 unDeBruijnTyM
     :: (MonadReader Levels m, MonadQuote m, MonadError FreeVariableError m)
-    => Type TyDeBruijn uni ann
+    => Type NamedTyDeBruijn uni ann
     -> m (Type TyName uni ann)
 unDeBruijnTyM = \case
     -- variable case
@@ -137,7 +139,7 @@ unDeBruijnTyM = \case
 
 unDeBruijnTermM
     :: (MonadReader Levels m, MonadQuote m, MonadError FreeVariableError m)
-    => Term TyDeBruijn DeBruijn uni ann
+    => Term NamedTyDeBruijn NamedDeBruijn uni ann
     -> m (Term TyName Name uni ann)
 unDeBruijnTermM = \case
     -- variable case
diff --git a/plutus-core/src/Language/PlutusCore/DeBruijn/Internal.hs b/plutus-core/src/Language/PlutusCore/DeBruijn/Internal.hs
index e7ed57d4cea..fc40ec041f2 100644
--- a/plutus-core/src/Language/PlutusCore/DeBruijn/Internal.hs
+++ b/plutus-core/src/Language/PlutusCore/DeBruijn/Internal.hs
@@ -8,7 +8,9 @@
 module Language.PlutusCore.DeBruijn.Internal
     ( Index (..)
     , DeBruijn (..)
+    , NamedDeBruijn (..)
     , TyDeBruijn (..)
+    , NamedTyDeBruijn (..)
     , FreeVariableError (..)
     , Level (..)
     , Levels (..)
@@ -19,6 +21,8 @@ module Language.PlutusCore.DeBruijn.Internal
     , withScope
     , getIndex
     , getUnique
+    , unNameDeBruijn
+    , unNameTyDeBruijn
     , nameToDeBruijn
     , tyNameToDeBruijn
     , deBruijnToName
@@ -50,31 +54,57 @@ newtype Index = Index Natural
     deriving anyclass NFData
 
 -- | A term name as a de Bruijn index.
-data DeBruijn = DeBruijn { dbnString :: T.Text, dbnIndex :: Index }
+data NamedDeBruijn = NamedDeBruijn { ndbnString :: T.Text, ndbnIndex :: Index }
+    deriving (Show, Generic)
+    deriving anyclass NFData
+
+-- | A term name as a de Bruijn index, without the name string.
+data DeBruijn = DeBruijn { dbnIndex :: Index }
     deriving (Show, Generic)
     deriving anyclass NFData
 
 -- | A type name as a de Bruijn index.
+newtype NamedTyDeBruijn = NamedTyDeBruijn NamedDeBruijn
+    deriving stock (Show, Generic)
+    deriving newtype (PrettyBy config)
+    deriving anyclass NFData
+instance Wrapped NamedTyDeBruijn
+
+-- | A type name as a de Bruijn index, without the name string.
 newtype TyDeBruijn = TyDeBruijn DeBruijn
     deriving stock (Show, Generic)
     deriving newtype (PrettyBy config)
     deriving anyclass NFData
 instance Wrapped TyDeBruijn
 
-instance HasPrettyConfigName config => PrettyBy config DeBruijn where
-    prettyBy config (DeBruijn txt (Index ix))
+instance HasPrettyConfigName config => PrettyBy config NamedDeBruijn where
+    prettyBy config (NamedDeBruijn txt (Index ix))
         | showsUnique = pretty txt <> "_i" <> pretty ix
         | otherwise   = pretty txt
         where PrettyConfigName showsUnique = toPrettyConfigName config
 
+instance HasPrettyConfigName config => PrettyBy config DeBruijn where
+    prettyBy config (DeBruijn (Index ix))
+        | showsUnique = "i" <> pretty ix
+        | otherwise   = ""
+        where PrettyConfigName showsUnique = toPrettyConfigName config
+
 class HasIndex a where
     index :: Lens' a Index
 
+instance HasIndex NamedDeBruijn where
+    index = lens g s where
+        g = ndbnIndex
+        s n i = n{ndbnIndex=i}
+
 instance HasIndex DeBruijn where
     index = lens g s where
         g = dbnIndex
         s n i = n{dbnIndex=i}
 
+instance HasIndex NamedTyDeBruijn where
+    index = _Wrapped' . index
+
 instance HasIndex TyDeBruijn where
     index = _Wrapped' . index
 
@@ -150,22 +180,30 @@ getUnique ix = do
         Just u  -> pure u
         Nothing -> throwError $ FreeIndex ix
 
+unNameDeBruijn
+    :: NamedDeBruijn -> DeBruijn
+unNameDeBruijn (NamedDeBruijn _ ix) = DeBruijn ix
+
+unNameTyDeBruijn
+    :: NamedTyDeBruijn -> TyDeBruijn
+unNameTyDeBruijn (NamedTyDeBruijn db) = TyDeBruijn $ unNameDeBruijn db
+
 nameToDeBruijn
     :: (MonadReader Levels m, MonadError FreeVariableError m)
-    => Name -> m DeBruijn
-nameToDeBruijn (Name str u) = DeBruijn str <$> getIndex u
+    => Name -> m NamedDeBruijn
+nameToDeBruijn (Name str u) = NamedDeBruijn str <$> getIndex u
 
 tyNameToDeBruijn
     :: (MonadReader Levels m, MonadError FreeVariableError m)
-    => TyName -> m TyDeBruijn
-tyNameToDeBruijn (TyName n) = TyDeBruijn <$> nameToDeBruijn n
+    => TyName -> m NamedTyDeBruijn
+tyNameToDeBruijn (TyName n) = NamedTyDeBruijn <$> nameToDeBruijn n
 
 deBruijnToName
     :: (MonadReader Levels m, MonadError FreeVariableError m)
-    => DeBruijn -> m Name
-deBruijnToName (DeBruijn str ix) = Name str <$> getUnique ix
+    => NamedDeBruijn -> m Name
+deBruijnToName (NamedDeBruijn str ix) = Name str <$> getUnique ix
 
 deBruijnToTyName
     :: (MonadReader Levels m, MonadError FreeVariableError m)
-    => TyDeBruijn -> m TyName
-deBruijnToTyName (TyDeBruijn n) = TyName <$> deBruijnToName n
+    => NamedTyDeBruijn -> m TyName
+deBruijnToTyName (NamedTyDeBruijn n) = TyName <$> deBruijnToName n
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore.hs
index 23d4929cf46..5682ea33456 100644
--- a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore.hs
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore.hs
@@ -5,6 +5,7 @@ module Language.UntypedPlutusCore
 
 import           Language.UntypedPlutusCore.Core               as Export
 import           Language.UntypedPlutusCore.Size               as Export
+import           Language.UntypedPlutusCore.Subst              as Export
 -- Also has some functions
 import           Language.UntypedPlutusCore.Core.Instance.CBOR as Export
 
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core.hs
index 11b0d04f982..67de3fe8caf 100644
--- a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core.hs
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core.hs
@@ -3,4 +3,5 @@ module Language.UntypedPlutusCore.Core
     ) where
 
 import           Language.UntypedPlutusCore.Core.Instance ()
+import           Language.UntypedPlutusCore.Core.Plated   as Export
 import           Language.UntypedPlutusCore.Core.Type     as Export
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Plated.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Plated.hs
new file mode 100644
index 00000000000..87729b6fe1c
--- /dev/null
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Plated.hs
@@ -0,0 +1,57 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE RankNTypes #-}
+
+module Language.UntypedPlutusCore.Core.Plated
+    ( termBinds
+    , termVars
+    , termUniques
+    , termSubterms
+    , termSubtermsDeep
+    , termUniquesDeep
+    ) where
+
+import           Language.PlutusCore.Core             (HasUniques)
+import           Language.PlutusCore.Name
+import           Language.UntypedPlutusCore.Core.Type
+
+import           Control.Lens
+
+-- | Get all the direct child 'name a's of the given 'Term' from 'LamAbs'es.
+termBinds :: Traversal' (Term name uni ann) name
+termBinds f = \case
+    LamAbs ann n t -> f n <&> \n' -> LamAbs ann n' t
+    x -> pure x
+
+-- | Get all the direct child 'name a's of the given 'Term' from 'Var's.
+termVars :: Traversal' (Term name uni ann) name
+termVars f = \case
+    Var ann n -> Var ann <$> f n
+    x -> pure x
+
+-- | Get all the direct child 'Unique's of the given 'Term'.
+termUniques :: HasUniques (Term name uni ann) => Traversal' (Term name uni ann) Unique
+termUniques f = \case
+    LamAbs ann n t -> theUnique f n <&> \n' -> LamAbs ann n' t
+    Var ann n -> theUnique f n <&> Var ann
+    x -> pure x
+
+{-# INLINE termSubterms #-}
+-- | Get all the direct child 'Term's of the given 'Term'.
+termSubterms :: Traversal' (Term name uni ann) (Term name uni ann)
+termSubterms f = \case
+    LamAbs ann n t -> LamAbs ann n <$> f t
+    Apply ann t1 t2 -> Apply ann <$> f t1 <*> f t2
+    Delay ann t -> Delay ann <$> f t
+    Force ann t -> Force ann <$> f t
+    e@Error {} -> pure e
+    v@Var {} -> pure v
+    c@Constant {} -> pure c
+    b@Builtin {} -> pure b
+
+-- | Get all the transitive child 'Term's of the given 'Term'.
+termSubtermsDeep :: Fold (Term name uni ann) (Term name uni ann)
+termSubtermsDeep = cosmosOf termSubterms
+
+-- | Get all the transitive child 'Unique's of the given 'Term'.
+termUniquesDeep :: HasUniques (Term name uni ann) => Fold (Term name uni ann) Unique
+termUniquesDeep = termSubtermsDeep . termUniques
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Type.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Type.hs
index d5c900b7f94..b050da4753a 100644
--- a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Type.hs
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Core/Type.hs
@@ -23,6 +23,7 @@ import qualified Language.PlutusCore.Constant                       as TPLC
 import qualified Language.PlutusCore.Core                           as TPLC
 import           Language.PlutusCore.Evaluation.Machine.ExBudgeting
 import           Language.PlutusCore.Evaluation.Machine.ExMemory
+import qualified Language.PlutusCore.Name                           as TPLC
 import           Language.PlutusCore.Universe
 
 -- | The type of Untyped Plutus Core terms. Mirrors the type of Typed Plutus Core terms except
@@ -64,6 +65,11 @@ instance TPLC.AsConstant (Term name uni ann) where
 instance TPLC.FromConstant (Term name uni ()) where
     fromConstant = Constant ()
 
+type instance TPLC.HasUniques (Term name uni ann)
+    = TPLC.HasUnique name TPLC.TermUnique
+type instance TPLC.HasUniques (Program name uni ann) = TPLC.HasUniques
+    (Term name uni ann)
+
 instance ToExMemory (Term name uni ()) where
     toExMemory _ = 0
 
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/DeBruijn.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/DeBruijn.hs
index 4ce7b1b991c..c414320c510 100644
--- a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/DeBruijn.hs
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/DeBruijn.hs
@@ -7,11 +7,13 @@
 module Language.UntypedPlutusCore.DeBruijn
     ( Index (..)
     , DeBruijn (..)
+    , NamedDeBruijn (..)
     , FreeVariableError (..)
     , deBruijnTerm
     , deBruijnProgram
     , unDeBruijnTerm
     , unDeBruijnProgram
+    , unNameDeBruijn
     ) where
 
 import           Language.PlutusCore.DeBruijn.Internal
@@ -32,19 +34,19 @@ This module is just a boring port of the typed version.
 -- | Convert a 'Term' with 'TyName's and 'Name's into a 'Term' with 'TyDeBruijn's and 'DeBruijn's.
 deBruijnTerm
     :: MonadError FreeVariableError m
-    => Term Name uni ann -> m (Term DeBruijn uni ann)
+    => Term Name uni ann -> m (Term NamedDeBruijn uni ann)
 deBruijnTerm = flip runReaderT (Levels 0 BM.empty) . deBruijnTermM
 
 -- | Convert a 'Program' with 'TyName's and 'Name's into a 'Program' with 'TyDeBruijn's and 'DeBruijn's.
 deBruijnProgram
     :: MonadError FreeVariableError m
-    => Program Name uni ann -> m (Program DeBruijn uni ann)
+    => Program Name uni ann -> m (Program NamedDeBruijn uni ann)
 deBruijnProgram (Program ann ver term) = Program ann ver <$> deBruijnTerm term
 
 deBruijnTermM
     :: (MonadReader Levels m, MonadError FreeVariableError m)
     => Term Name uni ann
-    -> m (Term DeBruijn uni ann)
+    -> m (Term NamedDeBruijn uni ann)
 deBruijnTermM = \case
     -- variable case
     Var ann n -> Var ann <$> nameToDeBruijn n
@@ -64,18 +66,18 @@ deBruijnTermM = \case
 -- | Convert a 'Term' with 'TyDeBruijn's and 'DeBruijn's into a 'Term' with 'TyName's and 'Name's.
 unDeBruijnTerm
     :: (MonadQuote m, MonadError FreeVariableError m)
-    => Term DeBruijn uni ann -> m (Term Name uni ann)
+    => Term NamedDeBruijn uni ann -> m (Term Name uni ann)
 unDeBruijnTerm = flip runReaderT (Levels 0 BM.empty) . unDeBruijnTermM
 
 -- | Convert a 'Program' with 'TyDeBruijn's and 'DeBruijn's into a 'Program' with 'TyName's and 'Name's.
 unDeBruijnProgram
     :: (MonadQuote m, MonadError FreeVariableError m)
-    => Program DeBruijn uni ann -> m (Program Name uni ann)
+    => Program NamedDeBruijn uni ann -> m (Program Name uni ann)
 unDeBruijnProgram (Program ann ver term) = Program ann ver <$> unDeBruijnTerm term
 
 unDeBruijnTermM
     :: (MonadReader Levels m, MonadQuote m, MonadError FreeVariableError m)
-    => Term DeBruijn uni ann
+    => Term NamedDeBruijn uni ann
     -> m (Term Name uni ann)
 unDeBruijnTermM = \case
     -- variable case
diff --git a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Subst.hs b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Subst.hs
index 38c9de4db0e..850c97c0428 100644
--- a/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Subst.hs
+++ b/plutus-core/untyped-plutus-core/Language/UntypedPlutusCore/Subst.hs
@@ -1,6 +1,13 @@
+{-# LANGUAGE LambdaCase          #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 module Language.UntypedPlutusCore.Subst
-    ( termSubstFreeNamesA
+    ( substVarA
+    , substVar
+    , termSubstNamesM
+    , termSubstNames
+    , termSubstFreeNamesA
     , termSubstFreeNames
+    , termMapNames
     ) where
 
 import           PlutusPrelude
@@ -15,6 +22,37 @@ import           Data.Set                        as Set
 purely :: ((a -> Identity b) -> c -> Identity d) -> (a -> b) -> c -> d
 purely = coerce
 
+-- | Applicatively replace a variable using the given function.
+substVarA
+    :: Applicative f
+    => (name -> f (Maybe (Term name uni ann)))
+    -> Term name uni ann
+    -> f (Term name uni ann)
+substVarA nameF t@(Var _ name) = fromMaybe t <$> nameF name
+substVarA _     t              = pure t
+
+-- | Replace a variable using the given function.
+substVar
+    :: (name -> Maybe (Term name uni ann))
+    -> Term name uni ann
+    -> Term name uni ann
+substVar = purely substVarA
+
+-- | Naively monadically substitute names using the given function (i.e. do not substitute binders).
+termSubstNamesM
+    :: Monad m
+    => (name -> m (Maybe (Term name uni ann)))
+    -> Term name uni ann
+    -> m (Term name uni ann)
+termSubstNamesM = transformMOf termSubterms . substVarA
+
+-- | Naively substitute names using the given function (i.e. do not substitute binders).
+termSubstNames
+    :: (name -> Maybe (Term name uni ann))
+    -> Term name uni ann
+    -> Term name uni ann
+termSubstNames = purely termSubstNamesM
+
 -- | Applicatively substitute *free* names using the given function.
 termSubstFreeNamesA
     :: (Applicative f, HasUnique name TermUnique)
@@ -41,3 +79,25 @@ termSubstFreeNames
     -> Term name uni ann
     -> Term name uni ann
 termSubstFreeNames = purely termSubstFreeNamesA
+
+-- | Completely replace the names with a new name type.
+termMapNames
+    :: forall name name' uni ann
+    . (name -> name')
+    -> Term name uni ann
+    -> Term name' uni ann
+termMapNames f = go
+    where
+        -- This is all a bit clunky because of the type-changing, I'm not sure of a nicer way to do it
+        go :: Term name uni ann -> Term name' uni ann
+        go = \case
+            LamAbs ann name body -> LamAbs ann (f name) (go body)
+            Var ann name -> Var ann (f name)
+
+            Apply ann t1 t2 -> Apply ann (go t1) (go t2)
+            Delay ann t -> Delay ann (go t)
+            Force ann t -> Force ann (go t)
+
+            Constant ann c -> Constant ann c
+            Builtin ann b -> Builtin ann b
+            Error ann -> Error ann
diff --git a/plutus-ledger/src/Ledger/Scripts.hs b/plutus-ledger/src/Ledger/Scripts.hs
index 303ddc2b526..8e55ed8bf07 100644
--- a/plutus-ledger/src/Ledger/Scripts.hs
+++ b/plutus-ledger/src/Ledger/Scripts.hs
@@ -137,8 +137,10 @@ fromCompiledCode :: CompiledCode PLC.DefaultUni a -> Script
 fromCompiledCode = fromPlc . getPlc
 
 fromPlc :: UPLC.Program PLC.Name PLC.DefaultUni () -> Script
-fromPlc p = case UPLC.deBruijnProgram p of
-    Right p' -> Script p'
+fromPlc (UPLC.Program a v t) = case UPLC.deBruijnTerm $ t of
+    Right t' ->
+        let nameless = UPLC.termMapNames UPLC.unNameDeBruijn t'
+        in Script $ UPLC.Program a v nameless
     Left _   -> Haskell.error "Debruijn failed"
 
 -- | Given two 'Script's, compute the 'Script' that consists of applying the first to the second.
@@ -155,7 +157,12 @@ data ScriptError =
 -- | Evaluate a script, returning the trace log.
 evaluateScript :: forall m . (MonadError ScriptError m) => Script -> m [Haskell.String]
 evaluateScript s = do
-    p <- case PLC.runQuote $ runExceptT $ UPLC.unDeBruijnProgram $ unScript s of
+    -- TODO: evaluate the nameless debruijn program directly
+    let namedProgram =
+            let (UPLC.Program a v t) = unScript s
+                named = UPLC.termMapNames (\(UPLC.DeBruijn ix) -> UPLC.NamedDeBruijn "" ix) t
+            in UPLC.Program a v named
+    p <- case PLC.runQuote $ runExceptT $ UPLC.unDeBruijnProgram namedProgram of
         Right p -> return p
         Left e  -> throwError $ MalformedScript $ show e
     let (logOut, _tally, result) = evaluateCekTrace p