In a large house in London’s fashionable Chelsea, a baby is awake in her cot. Well-fed and cared for, she is happily waiting for someone to pick her up.

In the kitchen lie three decomposing corpses. Close to them is a hastily scrawled note.

They’ve been dead for several days.

Who has been looking after the baby?

And where did they go?

Two entangled families.

A house with the darkest of secrets.