John Kelley, known by his code name, Mr. Clark, is a former Navy SEAL and Vietnam veteran. He is still getting over the accidental death of his wife six months before, when he befriends a young woman with a decidedly checkered past. When that past reaches out for her in a particularly horrifying fashion, he vows revenge and, assembling all of his old skills, sets out to track down the men responsible, before it can happen again