When carefree bachelor David Sloane tries to persuade his best friend Harry Hunter to drop his mistress Carol Corman and return to his wife Mary, other romantic problems suddenly spring to life.

Battle-of-the-sexes comedy about a free-wheeling bachelor who decides to save his friend's marriage by proving that all mistresses are incapable of fidelity. The plot gets complicated when the bachelor offers to set up the wrong girl in a lavish love-nest and she accepts, believing that it's a marriage proposal.—alfiehitchie