Peter Gruber, a young tenor from Vienna, gives piano lessons to Daisy, the daughter of a dentist. They fall in love and when Gruber has to perform in Antwerp, Daisy follows him there. She pretends to be an American musician and manages to get a job with Gruber's orchestra. Daisy's worried father sets off in pursuit of his daughter, accompanied by a certain miss Lola.

When his colleague presents him with (forged) evidence of his wife Sylvette's unfaithfulness, factory owner Jean Sourdier kills him in a fit of rage. After fifteen years in prison he is determined to take revenge on his wife by killing Ninette, a daughter from her second marriage.

Hugo Writley, the son of an American shipping magnate, travels to Holland accompanied by his steward, Longway. On the night of their arrival they go to a cabaret, where they get into conversation with two men and their girlfriends who, at closing time, invite the Americans to their home for a few drinks. The hosts, however, turn out to be 'land-sharks' planning to strip the two inebriated Yankees of their cash.