diff --git a/lib/step.js b/lib/step.js
index b524a6a..83a0ee6 100755
--- a/lib/step.js
+++ b/lib/step.js
@@ -29,7 +29,7 @@ function Step() {
       pending, counter, results, lock;
 
   // Define the main callback that's given as `this` to the steps.
-  function next() {
+  function next(err, data) {
     counter = pending = 0;
 
     // Check if there are no steps left
@@ -70,7 +70,7 @@ function Step() {
     var index = 1 + counter++;
     pending++;
 
-    return function () {
+    return function (err, data) {
       pending--;
       // Compress the error from any result to the first argument
       if (arguments[0]) {
@@ -105,7 +105,7 @@ function Step() {
     return function () {
       var index = counter++;
       pending++;
-      return function () {
+      return function (err, data) {
         pending--;
         // Compress the error from any result to the first argument
         if (arguments[0]) {