A lie spirals out of control for an already guilt-ridden Donna.

Max has discovered that someone has been stealing Diazepam, and proposes new rules to restrict access - a move that threatens to cut off Faith's supply and bring her secrets into the light. When Cam forgets to sign for a patient's morphine, Stevie becomes suspicious that he is behind the missing drugs. Donna's conscience is troubled further when a familiar patient is checked in.