When a subway train is thrown off the track by 60,000 gallons of flood water, a partially skeletonized body emerges out of the overflow. While Dr. Sweets, a passenger on the derailed train, copes with post traumatic stress, the rest of the team and intern Daisy Wick get to work on identifying the victim as Martin Aragon, a professional ghost writer caught up in a deadly love triangle. Meanwhile, Brennan releases her second book to great success, but has to accommodate a nosy reporter, and Sweets' near-death experience leads him to make a drastic decision.