diff --git a/lib/step.js b/lib/step.js
index e91239b..546c14d 100755
--- a/lib/step.js
+++ b/lib/step.js
@@ -26,7 +26,7 @@ SOFTWARE.
 // modified to fit my taste and the node.JS error handling system.
 function Step() {
   var steps = Array.prototype.slice.call(arguments),
-      counter, results, lock;
+      pending, counter, results, lock;
 
   // Define the main callback that's given as `this` to the steps.
   function next() {
@@ -42,7 +42,7 @@ function Step() {
 
     // Get the next step to execute
     var fn = steps.shift();
-    counter = 0;
+    counter = pending = 0;
     results = [];
 
     // Run the step in a try..catch block so exceptions don't get out of hand.
@@ -64,11 +64,11 @@ function Step() {
 
   // Add a special callback generator `this.parallel()` that groups stuff.
   next.parallel = function () {
-    var i = counter;
-    counter++;
+    var index = 1 + counter++;
+    pending++;
 
     function check() {
-      if (counter === 0) {
+      if (pending === 0) {
         // When they're all done, call the callback
         next.apply(null, results);
       }
@@ -76,13 +76,13 @@ function Step() {
     process.nextTick(check); // Ensures that check is called at least once
 
     return function () {
-      counter--;
+      pending--;
       // Compress the error from any result to the first argument
       if (arguments[0]) {
         results[0] = arguments[0];
       }
       // Send the other results as arguments
-      results[i + 1] = arguments[1];
+      results[index] = arguments[1];
       if (!lock) { check(); }
     };
   };
@@ -91,11 +91,12 @@ function Step() {
   next.group = function () {
     var localCallback = next.parallel();
     var counter = 0;
+    var pending = 0;
     var result = [];
     var error = undefined;
 
     function check() {
-      if (counter === 0) {
+      if (pending === 0) {
         // When group is done, call the callback
         localCallback(error, result);
       }
@@ -104,16 +105,16 @@ function Step() {
 
     // Generates a callback for the group
     return function () {
-      var i = counter;
-      counter++;
+      var index = counter++;
+      pending++;
       return function () {
-        counter--;
+        pending--;
         // Compress the error from any result to the first argument
         if (arguments[0]) {
           error = arguments[0];
         }
         // Send the other results as arguments
-        result[i] = arguments[1];
+        result[index] = arguments[1];
         if (!lock) { check(); }
       };
     };
diff --git a/test/groupTest.js b/test/groupTest.js
index 81798cc..c1124ab 100644
--- a/test/groupTest.js
+++ b/test/groupTest.js
@@ -45,4 +45,58 @@ Step(
     fulfill('five');
     assert.deepEqual(results, []);
   }
+);
+
+// Test lock functionality with N sized groups
+expect("test3: 1");
+expect("test3: 1,2,3");
+expect("test3: 2");
+Step(
+    function() {
+        return 1;
+    },
+    function makeGroup(err, num) {
+        if(err) throw err;
+        fulfill("test3: " + num);
+        var group = this.group();
+        
+        setTimeout((function(callback) { return function() { callback(null, 1); } })(group()), 100);
+        group()(null, 2);
+        setTimeout((function(callback) { return function() { callback(null, 3); } })(group()), 0);
+    },
+    function groupResults(err, results) {
+        if(err) throw err;
+        fulfill("test3: " + results);
+        return 2
+    },
+    function terminate(err, num) {
+        if(err) throw err;
+        fulfill("test3: " + num);
+    }
+);
+
+// Test lock functionality with zero sized groups
+expect("test4: 1");
+expect("test4: empty array");
+expect("test4: group of zero terminated");
+expect("test4: 2");
+Step(
+    function() {
+        return 1;
+    },
+    function makeGroup(err, num) {
+        if(err) throw err;
+        fulfill("test4: " + num);
+        this.group();
+    },
+    function groupResults(err, results) {
+        if(err) throw err;
+        if(results.length === 0) { fulfill("test4: empty array"); }
+        fulfill('test4: group of zero terminated');
+        return 2
+    },
+    function terminate(err, num) {
+        if(err) throw err;
+        fulfill("test4: " + num);
+    }
 );
\ No newline at end of file
diff --git a/test/parallelTest.js b/test/parallelTest.js
index c579e96..6a78853 100644
--- a/test/parallelTest.js
+++ b/test/parallelTest.js
@@ -20,3 +20,30 @@ Step(
     assert.equal(etcText, users, "Users should come second");
   }
 );
+
+// Test lock functionality with N sized groups
+expect("test2: 1");
+expect("test2: 1,2,3");
+expect("test2: 2");
+Step(
+    function() {
+        return 1;
+    },
+    function makeParallelCalls(err, num) {
+        if(err) throw err;
+        fulfill("test2: " + num);
+        
+        setTimeout((function(callback) { return function() { callback(null, 1); } })(this.parallel()), 100);
+        this.parallel()(null, 2);
+        setTimeout((function(callback) { return function() { callback(null, 3); } })(this.parallel()), 0);
+    },
+    function parallelResults(err, one, two, three) {
+        if(err) throw err;
+        fulfill("test2: " + [one, two, three]);
+        return 2
+    },
+    function terminate(err, num) {
+        if(err) throw err;
+        fulfill("test2: " + num);
+    }
+)
\ No newline at end of file