A small boy, frustrated by a lack of friends or attention from his businessman father, stows away on the Posieden, and soon becomes friends with Crunch and Des. They teach him some fishing skills, which he tells another kid, demonstrating with a rod he has stolen from the ship, only to lose it.
To test some survival equipment, Crunch and Des set out in a raft floating near the Posiedon for a few hours. But when the ship's crew is asked to rescue some wreck survivors, they abandon the duo, who now face a dangerous storm and rough seas.
While police search for killer jewel thieves, Crunch and Des land a strange fish that might be a valuable primitive coelacanth-like creature, but are unsure. Two college professors show up and decide it is and have it sent to their upstate lab, but suspicions soon set in when it's revealed as a modern day trout.