 A strange group of passengers embarks on a luxury liner when the news is announced that the fabulous Omar diamond is to be taken to the United States by a gem dealer. Victor Morrell (Cesar Romero) is aboard posing as an owner of an Argentine cattle ranch, as is Valerie Barton (Phyllis Brooks), interested in the diamond and traveling with her aunt, Cnthia Barton (Jane Darwell). Others aboard are Julien Stevens (Alan Dinehart), a blustering suit manufacturer, and two out-and-out crooks, Phil (Leon Ames) and Monet (Albert Conti). All have the idea that Morell is after the diamond and declare themselves in whether he likes it or not. Valerie plays upon Morell s interest in her to make him give up his attempt to get the diamond so she can have a clear field.