A deadly subway collision is investigated as a New York City medical examiner attempts to discover the truth behind his inexplicable immortality.

Henry and Jo become immersed in the world of a dominatrix, who doesn't dole out pain for kinky pleasures but for therapeutic purposes. Meanwhile, Abe reacquaints himself with his own form of pain and pleasure - his former wife.

Henry and Adam have been on a long, unrelenting collision course, which is about to come to a head – possibly bringing about one man’s death – with only Jo standing in the way. Henry and Jo’s murder investigation into a museum worker’s death centers on a priceless missing ancient dagger, which not only ended the life of Julius Caesar, but also killed Adam the first time. Meanwhile, Adam knows that there is something that Henry fears more than death – that Jo might discover his mystery. The two men tangle in a tumultuous game-changing confrontation. But at long last, will Jo finally learn about Henry’s secret?