First Casualty: Part 1

At Hillsdon Army base, a training camp for soldiers fighting in Afghanistan, young soldier Mark Blakefield is still recovering from the death in action of his friend Danny Ferris and argues with Lieutenant Lockford, who was having an affair with Danny's girl-friend 'Cats' Felton, a fact which Lockford's wife Claire has also discovered. Cats' body is pulled from the river some time after she was talking to the lieutenant and Nikki suspects foul play. Then Lockford is shot, an apparent suicide, but Harry, accompanying Inspector Suzy Harte to the base, finds from the postmortem result that the man was murdered.