A sleep-deprived new mother approaching her fortieth birthday, the very last thing Louisa wants to do is celebrate.

But when her friend Tiff organises a surprise party, inviting the entire list of Louisa's Facebook friends, Louisa is faced with a room full of people she hasn't spoken to in years - including someone she never expected to see again: her ex-boyfriend, Oliver Dunmore.

When Oliver's wife Melissa goes missing after the party, everyone remembers the night differently. Someone knows what happened to Melissa, and Louisa is determined to find them. But the truth could be closer, and the deception more devastating, than she'd ever imagined...