diff --git a/__concurrent/surelock-demo/src/main.rs b/__concurrent/surelock-demo/src/main.rs
index e7a11a9..2bfa978 100644
--- a/__concurrent/surelock-demo/src/main.rs
+++ b/__concurrent/surelock-demo/src/main.rs
@@ -1,3 +1,11 @@
+use surelock::{key_handle::KeyHandle, mutex::Mutex};
+
 fn main() {
-    println!("Hello, world!");
+    let counter: Mutex<u32> = Mutex::new(0);
+
+    let mut handle = KeyHandle::claim();
+    handle.scope(|key| {
+        let (mut guard, _key) = key.lock(&counter);
+        *guard += 1;
+    });
 }