Wealthy doctor Tom Kendrick (David Tennant) is the sole survivor of a tragic fire that kills his three daughters and his troubled wife Kate (Anna Madeley). However, their close friend - and Tom's mistress - Jess (Cush Jumbo) and her policeman partner Steve (Matthew McNulty) come to suspect that something far worse happened.
- Pregnancy Makes You Crazy: Kate's severe depression and anxiety that apparently led to her killing her children was caused by her pregnancy.
- Law of Inverse Fertility: Jess and Steve have been trying to have a baby for what seems to be a while at the beginning of the series (they're already trying various fertility treatments), but the treatments have no effect and by the end of the series they are still unsuccessful.
- Sole Survivor: Tom is one of the fire.
- Who Needs Enemies?: Jess and Kate are supposed to be friends, but Jess seemed completely unaware of the tragedy unfolding in Kate's personal life.
