Sophie and Monique are identical twins growing up in 1950's America. During childhood, Monique makes the discovery that the game of swapping identities with Sophie grants her immense power over others. As a grown woman, Sophie meets and ultimately marries Matt, an eccentric, hard-driven rich man with mysteries in his past. Unexpectedly one day Sophie contacts Monique to plead with her twin for help in escaping from what has now become an oppressive marriage. Trapped because of Matt's threats of violence if she leaves him, Sophie needs to find some other way to save herself and her young daughter. Monique devises a plan to help Sophie, and so the two sisters prepare to become each other one last time. Monique, however, has no real handle on either who Matt really is or where his inner torment comes from. More importantly, Monique has no way to know, but is about to discover, where his anguish will take not only him-but soon herself as well.