Tasha has always felt in the shadow of her older sister, Alice. Alice is married to wealthy entrepreneur Kyle and has a high-flying career, Tasha is married to her childhood sweetheart and lives in a Bristol suburb with their three-year-old twins.

When Alice realises that Tasha is struggling she suggests she come to look after the twins for a week, so Tasha and her husband can enjoy a trip away.

But a few days in, it all goes terribly wrong. Tasha receives a phonecall to say Alice is in hospital and Kyle is dead after an intruder broke into their house. A burglary gone wrong, surely. Until a note arrives saying It was supposed to be you...