When a spoiled kid disappears, the Casebusters go spelunking with a pirate's ghost Sean and Brian Quinn have never liked Lester Hopper. The seven-year-old is spoiled rotten, and looks down on every kid he knows—even the ones who are taller than him! But one night, Lester disappears and a ransom note warns the Hoppers not to contact the police. The Casebusters are going to need to solve their most serious mystery yet—a possible kidnapping. Before he disappeared, Lester was diagnosed with a lung infection, and he needs to take his medicine again soon or he'll get very sick indeed. But was Lester kidnapped, or did he run away? Whatever the answer, all the clues point to one destination: the town's oldest cave, which is said to be haunted by the ghost of a dead pirate. To save Lester, Brian and Sean will have to match wits with a swashbuckler who's been dead for centuries.