Ballistics comparison tests performed on bullets recovered from several murders indicate that they were fired from the same gun - but one that could not possibly have been used, because during each time the lethal shots were fired, the weapon was in the custody of the authorities. District Attorney Myra Scot Sharp (attorney Peter Sharp's bitter ex-wife) appoints a special prosecuting investigator, but when she and all the other adults involved fail to solve this mystery, little Suzi B. is called in for assistance and tries to prove that her amazing theory about who the murderer is, even though it contradicts the opinions of every police agency involved. Is Suzi right or wrong this time? You'll be as surprised as Peter, Myra, and the police are when Suzi conducts an experiment on the boat that will determine the innocence or guilt of the person that she suspects is guilty.