"For the last three years in the month of October, all of Boston lived in fear of a ruthless serial killer mutilating indiscriminately, and this year is no different. A murder occurs in a city park. An old Irish/Scottish legend stemming from earlier Celtic times talks of an evil spirit who was rejected by Satan himself. It was doomed to walk the earth forever, haunting the woods and bogs. The spirit manifests itself as light orbs, or the Will O' the Wisp - better known as Jack O' Lantern. It is said that it will possess a man weak of soul to carry out unthinkable acts in hopes of being accepted into Hell. In rural Ireland in the 15th century, a powerful man possessed by Jack O' Lantern is wreaking havoc. Jesuit priests with divine gifts arrive and trap the spirit. They barricade the trapped spirit in the back of the Cave of the Cats believed by ancients to be the portal to Hell. They purposely collapse that section of the cave. The Jack O' Lantern is inadvertently released by a sociopath five years ago, who immediately becomes possessed by the spirit. This evil incarnate travels to Boston and soon begins its Satanic agenda. The serial killer task force has few fruitful leads and is making no headway until a man with a unique, divine gift joins the fray - the Watchmaker. He is Dr. Edward Dunham, a forensic scientist at the FBI lab in Quantico, Virginia. Since joining serial killer task forces out in the field beginning nearly a decade earlier, he has had a perfect record identifying the offender. His reputation now precedes him, so much so that fellow law enforcement personnel continue to spread the Watchmaker nickname. Being agnostic, Dunham does not believe he has a divine gift, a gift that a serial killer he once caught explained as being a "gift of the knowledge of good and evil" symbolically represented by one of the two trees in the Garden of Eden. He rejects this and merely attributes his success to training, education, team work, and luck. Identifying the killer is one thing; apprehending him is another. The task force nearly catches the killer on a number of occasions, but he easily evades them. A Jesuit priest who is also divinely gifted, though in his case it is the ability to control evil spirits, is secretly tasked by the Church to follow Dunham. Dunham soon discovers the priest's mission and both eventually team up. A freshman at Boston University, Rob Faulks, met Dunham in Buffalo, New York, the previous year when his sister was the object of a serial killer's desire. His efforts helped apprehend the serial offender. This year, he forms his own team of novice detective sleuths composed of fellow college students, and again surprises Dunham with timely assistance. Dunham sees a gift in Rob and takes him under his wing. In order to save the last victim, Dunham has to choose between what his head is telling him (logic) and what his gut is telling him (his divine gift). While he chooses his head, the priest chooses what Dunham's gut was saying, and the evil spirit is successfully captured"--