Glenda Lawson believes her husband was the only US serviceman shot and killed on American soil during World War II. But in 1945, investigators ruled that Billy Lawson died in a “mugging turned ugly.” Sean O’Brien is learning the ropes of commercial fishing when he gets his anchor caught on something underwater. He discovers a German U-boat partially buried in sand, and inside is a frightening cargo. The media pick up the story, and a 35-year-old woman who has a haunting tale visits O’Brien. Her grandfather, Billy Lawson, was fishing one night on a Florida beach when he saw something very disturbing. The Black Bullet is a thriller that combines an unsolved murder from 1945 and a modern-day discovery connected to America’s entry into nuclear weapons, the Manhattan Project. The last thing Sean O’Brien wants is to investigate a 67-year-old murder. But Billy Lawson’s granddaughter and his cancer-stricken widow are desperate for closure. For O’Brien to bring it to them he has to pry the lid off a secret buried with the Manhattan Project. It’s information that got Billy Lawson killed, and O’Brien soon learns the old murder and his new discovery at the bottom of the sea are inextricably knotted. O’Brien is thrust into a world where nothing is as it appears, and everything is riding on a secret Billy Lawson took to his grave.