After attorney Frank Girard is murdered, Detective Al Church suspects that Ms. Leigh Cullen is the perpetrator, as she was supposedly last seen with the man. However, after Leigh's alleged twin sister, Tracy, shows up at the police line-up with Leigh, Church is left puzzled and with no specific suspect to pinpoint. Therefore, Church asks Psychiatrist Dr. Jim Eiseley, an acquaintance of Leigh's, to evaluate the sisters and run tests on them in hopes of filtering out the murderer. However, Eiseley's increasing involvement with Leigh complicates things with Tracy in the picture.

Dominick and Eugene are twins, but Dominick is a little bit slow due do an accident in his youth. They live together, with Dominick working as garbage man to put Eugene through medical school. Their relationship becomes strained when Eugene must decide between his devotion to his brother, or his need to go away to complete his training. Things are also not helped by Dominick's co-worker, or Eugene's budding romance.