The sense of claustrophobia. The ping of the sonar. Breath held and sweat dripping as you await the depth charges. The groan of the superstructure and the popping of rivets as you descend deeper than you are supposed to. Submarine stories all come with their own inbuilt excitement. This one features nothing less than a murder on board and a potential nuclear war. Couple that with a secondary 'above ground' investigation into what happened all those years ago and have a double whammy from one of today's great thriller writers.