Charlie Chan in Honolulu (1938)

With Charlie Chan distracted by the imminent birth of his first grandchild, young Tommy Chan persuades his older brother Jimmy (eager to be a detective) to take Pop's place when a call comes in directing Charlie to investigate a murder aboard a freighter. Charlie eventually learns of this and boards the ship to straighten out its slew of suspects, a cargo hold full of wild animals, and two well-meaning but ineffectual sons.