It is early in the war and the Germans are after diamonds for their industrial war machine. Private detective Shayne (Lloyd Nolan) is in trouble with his girlfriend Merle (Mary Beth Hughes) who doesn't approve of his job, so he pretends to be working as a riveter instead. This however gets him onto the trail of a gang stealing industrial diamond. When the trail leads him to an ocean liner bound for Hawaii he has a problem, he has no money! He basically steals the money from his girlfriend so he can get a berth!
Shayne gets into a number of antics on board the ship, including various attempts on his life. His real trouble comes when he arrives in Honolulu. Merle has caught up to him and is arrested! Shayne is in a race against time to find out who is the leader of the gang, and that reveal is a big surprise!
This is a pretty decent film, an excellent example of a crime B-movie. A lot of story is packed in and it all makes sense too.
