The Naval Treaty recap

Foreign Office clerk Percy Phelps is entrusted with copying a secret naval treaty, but it disappears when he briefly leaves the room. The shock causes a long illness, and neither the police nor Holmes initially finds the document. Percy recuperates at his fiancée Annie Harrison's family home, where a nighttime intruder later tries to enter his room. Holmes realizes the incident concerns the treaty itself. He arranges for the room to be left unwatched and catches Annie's brother Joseph retrieving the paper from beneath the floor covering. Joseph had opportunistically stolen it during a visit to Percy's office and hidden it in his own bedroom, but Percy's unexpected illness kept him from reaching the hiding place. Holmes returns the intact treaty, clearing Percy and preventing a diplomatic crisis.

Percy Phelps, an old schoolmate of Watson and a Foreign Office clerk, is assigned to copy a highly secret naval treaty. Working alone after hours, he orders coffee and then goes downstairs when it does not arrive. A bell rings in the office above, but when Percy returns the treaty is gone. The building staff, including commissionaire Tangey and his wife, are investigated without result. Percy collapses with brain fever and spends weeks at his fiancée Annie Harrison's family home in Woking. Holmes interviews Percy, Inspector Forbes, and Foreign Secretary Lord Holdhurst, but learns that no foreign power has acted on the document. Then someone tries to enter Percy's sickroom through the window during the night. Holmes recognizes that the room, not Percy, is the intruder's target. He orders Annie to remain there for the day, lock it when she leaves, and let Percy stay elsewhere. Watching that night, Holmes catches Annie's brother Joseph entering and taking the treaty from beneath the floor covering. Joseph had visited Percy's office on the night of the theft, found the copying room empty, and taken the paper impulsively. He hid it in his own bedroom at home, but Percy's illness caused that room to be occupied and continuously watched before Joseph could dispose of it. Holmes recovers the treaty intact and returns it to Percy, ending the threat to his career and to British diplomacy.

Holmes catches Joseph Harrison entering Percy's room at night and retrieving the treaty from its hiding place beneath the floor covering. Joseph had called at the Foreign Office on the night Percy was copying it, found the room briefly empty, and seized the document on impulse. At home he concealed it in his bedroom, only to lose access when the feverish Percy was installed there and Annie maintained an almost continuous watch. His apparent attack at the window was an earlier effort to recover it. Holmes restores the treaty to Percy with a theatrical breakfast-table surprise. The document has not been sold, Percy is cleared of negligence beyond leaving the room, and the diplomatic danger ends. Annie's loyal care is vindicated, while her brother is exposed as the thief.