An American Navy veteran is hired to help search for sunken treasure, only to discover an intact Second World War submarine. One of his employers hatches a plan to repair the vessel and use it to hijack the Queen Mary ocean liner so they can steal its cargo of gold. Action adventure, with Frank Sinatra, Virna Lisi and Alf Kjellin.

A group of adventurers refloat a WWII German submarine and prepare to use it to pull a very large heist; The Queen Mary which they plan to rob on the high seas.