The film opens with a short clip showing the parasitic lifecycle of cuckoos, who lay their eggs in the nests of other birds.

The film opens with pub landlord and frequent holidaymaker Vic Flange (Sid James) openly flirting with the sassy saucepot widow Sadie Tompkins (Barbara Windsor) as his battleaxe wife, Cora (Joan Sims), looks on with disdain.

Laura Hall dies by suicide after her ex-husband Richard informs her he plans to marry Grace Marshall, a woman he met while researching a book about an extremist Christian cult.

Rachel Watson (Emily Blunt) is an on-off recovering alcoholic who aimlessly rides a train into New York City every day after losing her job and her marriage.

An aspiring costume designer moves into a one-bedroom apartment in Los Angeles, unaware that the complex is owned by a cult who use torture to force new residents to join their community.

Sawyer Valentini is a troubled woman who moves away from her home in Boston to escape a stalker.

The film begins with a teenage girl, Laurel Miller (Jessica Lowndes), going into the woods to meet her boyfriend Michael (Randy Wayne).