Sam Ryan is under great stress when she learns that she may have a tumor. As a result, she starts to question her judgment when she misses a possible explanation in determining the time of death in the case of Lloyd Dupen's wife, an apparent suicide. She's not convinced however that everything is above board and agrees to undertake a second autopsy at the request of the dead woman's mother. She's also asked by Bishop Craig to perform an autopsy on the remains of Sister Constance, a beatified nun who died forty years ago and is under consideration for canonization. The results of the autopsy will have an impact on the religious order as well as many of those in the community who see the commercial advantages of having a local saint.

Sam's medical condition seems to worsen as rumours fly about her losing her job due to bad judgement.

The team investigates the derailment of a train caused by someone leaving Maj. Mark Wiltshire's Land Rover on the tracks. The army is suspected but Wiltshire was in the officers mess at the time. The team have yet to identify the 21st victim, or determine if that person was on the train or in the car. Working with a survivor's group, they try to re-create where everyone was seated just prior to the crash occurring. When one of the survivors commits suicide, the crash claims its 22nd victim.

The investigation continues and one of the survivors remembers a vital piece of information. It becomes evident that the identification of body 21 may also lead to the cause of the crash. In the end, the solution rests on discovering a an unknown romantic affair and marital betrayal.