Washed-up true-crime writer Ellison Oswalt finds a box of super 8 home movies that suggest the murder he is currently researching is the work of a serial killer whose work dates back to the 1960s.

A young mother and her twin sons move into a rural house that's marked for death.

Five thirty-something couples decide to indulge in some friendly partner swapping with disastrous results for their marriages and friendship.