A young man grieving the loss of his twin brother joins a support group for "twinless twins."

As poor business and loneliness tolls on private detective Philip Marlowe, a beautiful blonde arrives and asks him to find her ex-lover, which proves to be just a small part in a bigger mystery.

Nellie is divorced by wealthy Jack Givens because after a miscarriage even in vitro fails to overcome her infertility. She finds herself destitute as her own accounts were plundered by someone who stole her maiden identity, Eleanor Kendall. Bank officer Dave, an old friend and potential lover, helps her trace the impostor to Montréal and prevent the imposter's purchase of a Corsica home. Nellie starts an affair with British doctor Christopher Dolan, who is in town for a conference, and bumps into Eleanor, a local French tutor and single mother. Instead of informing the police, she gets acquainted with and comes to like 'Eleanor'. Finally the truth catches up, but proves more complex and perilous than anyone anticipated.