Sam makes an unusual bet with a smoker anxious to quit, while Andrew tries to help a farmer whose failing health has driven him to take desperate measures.

Tragedy looms as Andrew and Sam try to save an injured man from a fast-flowing river, only too aware that his life rests in their hands.

Sam is tormented by the thought that he could have done more to help Andrew and Joanna's teenage patient recoils from the prospect of an operation.