Mike Barratt and his team are at crisis point when faced with a case of the deadly and contagious disease diphtheria when two Ukrainian sisters are admitted. Nick Jordan has to face his negligence hearing on the death of Janice Alexander, which gets off to a very shaky start. Karen decides that their marriage is finished.

Mike Barratt leads his team on the team-building course, but he steps on an illegal animal trap and breaks his leg. The others must quickly improvise treatment out in the field, or Barratt could lose his leg, or even his life.