Katie prided herself on being a responsible big sister - until she left her brother Chris alone for one selfish afternoon, and he became the victim of a vicious attack. Although he survived, the scars ran deep. Now they're adults, and they haven't spoken in years. Then she gets a call. A body has been found - and Chris is the prime suspect. Katie sees this as a chance to save her brother. But she doesn't realise that this isn't the first murder - and so she doesn't know how much danger she's in ...