S4, E2: When Stone takes Ezekiel to see an old friend at the racetrack / casino, he's expecting to get away from the headaches associated with being a Librarian. Once Stone and Ezekiel get to the racetrack, however, it quickly starts to feel like they haven't gotten a break from being Librarians at all. When Stone's friend, Slayton, loses his prize racehorse on a bet and is injured in a freak accident, they chalk it up to bad luck. Once they get to the hospital and find that the whole emergency room is full of victims of "freak accidents", all of whom were patrons of the same racetrack / casino, well, this sounds like a job for the Librarians.