A military-issue fragmentation grenade is used in an attack on two Vietnam veterans, one of whom - a friend of Mark's - is killed. When it transpires that another of the pair's old unit has come under similar attack, the Chief sets out to trap the killer, using Ed in a cunning disguise as bait.

A girl thought to have died years previously turns up at the home of her mother just as her brother is found murdered. Clearly somebody is trying to kill the family off, but is it connected to the girl, and is she really who she says she is?