Four Couples. Summer 1979. In the idyllic suburban neighbourhood of Ridgefield, during a scorching heat wave, four couples gather for their weekly dinner party.

An ordinary evening. It's a chance for friends to catch-up, to show off their perfect marriages, to have a break from the kids... but secrets hide behind the lit-up picture windows and carefully curated lawns.

The beginning of a nightmare. When Frank Callaghan checks on the sleeping children, he finds an empty crib where his 4-month old daughter Megan should be sleeping. The party-goers swear they didn't see anything. No one left the dinner table.

Forty years later, Megan's sister Amanda is still searching for answers when a stranger knocks at her door claiming to be Megan. The family are sceptical until they see what she is holding - Megan's blanket, taken the night she disappeared.

This shock appearance unearths many questions: Where has Megan been all of this time? Who knows what happened that night? And how well do you really know your neighbours?