The Letter Inside the Piano

Then she noticed something.

One key… slightly higher than the others.

“Probably broken,” she whispered.

But curiosity got the better of her.

She pressed it harder.

Click.

A faint mechanical sound echoed inside the piano.

Emily froze.

“…What was that?”

Her hands trembled as she leaned closer.

Carefully, she reached inside the piano… and felt something hidden behind the wood.

A small envelope.

Old.

Sealed.

And covered in dust.

Her heart started racing.

Why would someone hide a letter inside a piano?

And more importantly…

who was it for?