On a crisp January morning, a group of third year nursing students gather in Nightingale House for a clinical lesson. One student will play the patient, while the others practice their nursing skills. But none of them is prepared for the demonstration's gruesome end.

Later, when a student dies by apparent suicide, Superintendent Adam Dalgliesh is sure her death must be connected to what happened during that fateful demonstration. But in order to prove this and uncover the truth, he must sweep away a cloud of secrets, lies and blackmail at the nursing school - before there are any more deaths.