Annoyed by a newspaper account that fails to give Sherlock Holmes proper credit for solving the Cunningham case, Dr. Watson goes to Scotland Yard to complain to Inspector Lestrade. While Watson is with the inspector, word arrives that a murder has been committed at the home of Lord Beryl.
Lestrade takes Watson with him, and sends word for Holmes to join them, but Holmes delays his departure because he is absorbed in a chemical experiment. When Lestrade and Watson arrive, Lady Beryl confesses to shooting the victim, an Austrian agent. Later, when they tell Holmes the facts of the case, Holmes is immediately convinced that Lady Beryl is innocent, and he sets out to find the real murderer.