On a trip to the New York Aquarium with her third-grade class, a teacher discovers a dead body.

For as long as crime boss Albert Mendoza (Everett Sloane) has been running a notorious ring of hired hit men, District Attorney Martin Ferguson (Humphrey Bogart) has been hunting him down. But Ferguson cuts a deal with Mendoza's henchman Joe Rico (Ted De Corsia), and the mob boss is finally arrested. However, Rico dies mysteriously before he can testify against Mendoza.