The missing millionaire of the title is Otto Brandt. Him and his yacht have disappeared somewhat under a cloud and a few important people are asking after him.

Following a request from Raymond (Air Commodore at this stage), the team track down Otto and his yacht to a small island in the Bahamas where he is planning a revolution in Cuba. The plan is thwarted, naturally, by the team, and the millionaire of the title murdered by a hot-headed cuban seeking revenge for the murder of his father many years before.