The working class twin sister of a callous wealthy woman impulsively murders her out of revenge and assumes the identity of the dead woman. But impersonating her dead twin is more complicated and risky than she anticipated.

Playboy songwriter Brad Allen's succession of romances annoys his neighbor, interior designer Jan Morrow, who shares a telephone party line with him and hears all his breezy routines. After Jan unsuccessfully lodges a complaint against him, Brad sets about to seduce her in the guise of a sincere and upstanding Texas rancher. When mutual friend Jonathan discovers that his best friend is moving in on the girl he desires, however, sparks fly.