DI Tess Fox’s first murder scene has two big problems. One, the victim was thrown from the balcony of a flat locked from the inside. Two, Tess knows him.

But the biggest problem of all is Tess’s half-sister, Sarah. She has links to the deceased and has the skills and criminal background to mastermind a locked-room murder. But she’s a con-artist, not a killer.

When two more bodies turn up, Tess now has three locked room mysteries to solve and even more reason to be suspicious of Sarah. Can she trust someone who breaks the law for a living, even if she is family?