HISTORY
Travelling aboard the S.S. Placeda cruise ship, Dr. Marlin holds half a set of plans for a secret weapon, the other half is held by Bert Pine. When Pine is murdered on a Panama cruise, Detective Speed and Rang-a-Tang intervene.
After discovering Count Von Meister has an alibi, Hy Speed sees a man overboard. The detective could not save the man. Checking the passenger list, only one a passenger named Martin Wheeler is missing.
Later, Dr. Marlin leaves the boat with an army officer. Rang-a-Tang and Detective Speed follow, discovering that Dr. Martin is actually Martin Wheeler disguised as the doctor. Speed takes the fake Army officer and Wheeler, who murdered Bert Pine and shoved Dr. Marlin overboard after recovering both halves of the plans.