Part 1 of 6: a thrilling new installment in this darkly compelling psychological thriller

It started with an anonymous note...

Sarah Taylor–Cox has the perfect life – a gorgeous husband, a picture–perfect house in the Hamptons and a beautiful baby, Elliot. Now, the invites are being sent out for Elliot's christening, and the Taylor–Coxes are determined the party will be the event of the year.

There's just one chink in Sarah's carefully constructed calm demeanour – her sister, Maisey, will be coming. The sisters used to be close, but now their lives couldn't be more different. Surely though, they will slip back into their old ways, and the party will go off without a hitch...

Then, Sarah's difficult relationship with Maisey is pushed to the back of her mind when she receives a note, one which makes her whole body shake with dread: I know your secret. I'm going to tell.