diff --git a/30_Cube/csharp/Game.cs b/30_Cube/csharp/Game.cs
index f02fa07e..70ada599 100644
--- a/30_Cube/csharp/Game.cs
+++ b/30_Cube/csharp/Game.cs
@@ -2,6 +2,7 @@ namespace Cube;
 
 internal class Game
 {
+    private const int _initialBalance = 500;
     private readonly IReadWrite _io;
     private readonly IRandom _random;
 
@@ -14,5 +15,42 @@ internal class Game
     public void Play()
     {
         _io.Write(Streams.Introduction);
+
+        if (_io.ReadNumber("") != 0)
+        {
+            _io.Write(Streams.Instructions);
+        }
+
+        PlaySeries(_initialBalance);
+
+        _io.Write(Streams.Goodbye);
     }
-}
\ No newline at end of file
+
+    private void PlaySeries(float balance)
+    {
+        while (true)
+        {
+            var wager = _io.ReadWager(balance);
+
+            var gameWon = PlayGame();
+
+            if (wager.HasValue)
+            {
+                balance = gameWon ? (balance + wager.Value) : (balance - wager.Value);
+                if (balance <= 0)
+                {
+                    _io.Write(Streams.Bust);
+                    return;
+                }
+                _io.WriteLine(Formats.Balance, balance);
+            }
+
+            if (_io.ReadNumber(Prompts.TryAgain) != 1) { return; }
+        }
+    }
+
+    private bool PlayGame()
+    {
+        return true;
+    }
+}
diff --git a/30_Cube/csharp/IOExtensions.cs b/30_Cube/csharp/IOExtensions.cs
new file mode 100644
index 00000000..a221ca5d
--- /dev/null
+++ b/30_Cube/csharp/IOExtensions.cs
@@ -0,0 +1,20 @@
+namespace Cube;
+
+internal static class IOExtensions
+{
+    internal static float? ReadWager(this IReadWrite io, float balance)
+    {
+        io.Write(Streams.Wager);
+        if (io.ReadNumber("") == 0) { return null; }
+
+        var prompt = Prompts.HowMuch;
+
+        while(true)
+        {
+            var wager = io.ReadNumber(prompt);
+            if (wager <= balance) { return wager; }
+
+            prompt = Prompts.BetAgain;
+        }
+    }
+}
\ No newline at end of file
diff --git a/30_Cube/csharp/Resources/NextMove.txt b/30_Cube/csharp/Resources/NextMove.txt
index 4cbe5496..2c3c0611 100644
--- a/30_Cube/csharp/Resources/NextMove.txt
+++ b/30_Cube/csharp/Resources/NextMove.txt
@@ -1 +1 @@
-Next move: 
\ No newline at end of file
+Next move:
\ No newline at end of file