Alain Moreau's investigation into the death of his identical twin brother leads him from the beauty of the south of France to the mean streets of New York City and into the arms of his brother's beautiful girlfriend. Pursued by ruthless Russian mobsters and renegade FBI agents, the duo race against time to solve his brother's murder and expose an international conspiracy.

Nicolas Cage is Charlie Kaufman, a confused L.A. screenwriter overwhelmed by feelings of inadequacy, sexual frustration, self-loathing, and by the screenwriting ambitions of his freeloading twin brother Donald. While struggling to adapt "The Orchid Thief," by Susan Orlean, Kaufman's life spins from pathetic to bizarre. The lives of Kaufman, Orlean's book, become strangely intertwined as each one's search for passion collides with the others'.

Elliot, a successful gynecologist, works at the same practice as his identical twin, Beverly. Elliot is attracted to many of his patients and has affairs with them. When he inevitably loses interest, he will give the woman over to Beverly, the meeker of the two, without the woman knowing the difference. Beverly falls hard for one of the patients, Claire, but when she inadvertently deceives him, he slips into a state of madness.