Flipper #3

In "Das geheimnisvolle Schiff," Bud and Flipper set out on a routine day at sea when they spot Dan in distress, shouting for them to leave. After retrieving a soda can with the desperate word "HELP" scrawled on it, they uncover a hidden operation: a boat loading crates onto a helicopter, one of which they discover contains rifles. As tension mounts, the boys race to alert their father’s boat and the Coast Guard, leading to a dramatic showdown with crooks fleeing on a rubber raft.

In "Die geheimnisvolle Insel," Flipper and the boys are swept off course by a sudden storm, ending up stranded on a mysterious island where they find an unconscious Mr. Merton and a thief hiding in his home. When the thief captures the boys, Flipper must swim to get help, leading to a tense struggle that ends with the boys overcoming their captor—though the thief escapes, leaving behind the late Mrs. Merton's jewelry. With Mr. Merton recovering and the mystery deepening, the trio must piece together what really happened on the island.