The best of Universal-International's followups to , casts Bud and Lou as mail-order private eyes. The boys champion the cause of boxer Arthur Franz, who has been framed for murder. Utilizing the formula created by Claude Rains in the original (1933), Franz vanishes before Dr. Gavin Muir's astonished eyes. Cloaked by invisibility, Franz talks Bud and Lou into helping him nab the real murderer, gangster Sheldon Leonard. A string of uproarious gags and comic setpieces is highlighted by a boxing-ring finale, wherein Lou, backed up by the invisible Franz, dukes it out with a behemoth prizefighter. A clever special-effects closing gag caps this delightful A&C vehicle.