Watson is asked to authenticate a lost story — one that claims to be an undiscovered Holmes case. The client is nervous. The manuscript is too perfect. Watson begins to read.

By the third page he recognizes the voice. By the fifth he sees the error only the real author would make. He looks up. The client is gone — and the door is locked from the outside.

Holmes is away. A young woman arrives at 221B with a case Watson could never refuse. She believes her brother was framed. The evidence says otherwise. Watson takes his pen and his revolver.

They trace the trail to the docks. The truth is uglier than he expected. Just when he thinks the case is closed, a familiar silhouette appears in the fog.

Watson attends a reunion of old soldiers. Among them is a face from Afghanistan — someone he thought had died. The man pulls him aside. He has a story that must be told before it is too late.

Watson listens. The tale involves stolen documents, a conspiracy, and a name Watson has heard in Holmes's rooms. He agrees to help. Then he notices the man's hands — and the fresh blood under his nails.

Watson sits at his desk, struggling with the next story. How much can he publish? How much must stay hidden? The doorbell rings. A stranger has come with a message from the past.

The message is in code. Watson deciphers it. The words point to a case Holmes never solved — and to a danger that has followed Watson home.

Lestrade sends a constable to Watson's practice. The man is not ill; he is afraid. He has seen something in the course of duty that he cannot report. He needs a doctor's discretion.

Watson hears him out. The story involves a body, a cover-up, and a high-ranking name. Watson promises to speak to Holmes. That night his surgery is broken into — and the constable has vanished.