Buzzy O'Brien, a bellhop at the Hotel Royale, is an irrepressible amateur sleuth. Consequently, he becomes suspicious when guest Kitty Monohan inquires about a man named Thadius Porter. On his way to deliver a telegram to Porter, Buzzy bumps into a man, who drops a claim check. Buzzy picks up the check and enters Porter's room, where he finds a dead body. Intrigued, Buzzy opens the telegram and reads a warning to watch for a woman with the initials K. M. Realizing that Kitty will be accused of the crime, Buzzy helps her escape from the police. She tells Buzzy that she had hoped Porter could help her find her missing brother Jim, who has been accused of stealing bonds from Porter's bank. Deducing that the man in #415 registered under the name of Elliott must be Jim Monohan, Buzzy goes to pay him a visit, but is knocked unconscious. When he comes to, he discovers the dead body of the owner of the claim check and an unconscious Elliott left to die in a bath tub filled with water. Upon regaining consciousness, Elliott confesses that he is Jim Monohan, and continues that Porter advised him to leave town until his name was cleared. Realizing that someone in the hotel must be acting as a go between for the stolen bond holders, Buzzy begins to suspect Fluger, the hotel detective, and persuades Jefferson, the porter, to help him search Fluger's room. Just as Buzzy uncovers a briefcase full of bonds, he turns around to face Fluger, who admits to the murders and announces that Buzzy is next on his list. Jefferson, hiding in the bathroom, overhears Fluger's threat and crawls out on the ledge, pretending that he is about to jump. Jefferson's plan works and a witness in the street calls the police, who arrive just in time to save Buzzy. Fluger then confesses that he killed Porter after the bank president stole his own bank's bonds, thus exonerating Kitty and Jim of all guilt.