A big fish contest at the Trading Post, the Hollisters' sporting goods store, has everybody in Shoreham competing. After Pete catches a Clown fish with a mysterious tag on it, another adventure begins for the eager young detectives. When the children's playmate, Bobby Reed, disappears in a leaky old boat, the whole family helps in the search.

Uncle Russ lends them his speedy cabin-cruiser, and they set off on a trip far down the winding river. After helping some hikers on shore, Pete, Pam and Mr. Hollister get lost in a fog on the way back to their boat, the Sweetie Pie. Pam's borrowed compass and Pete’s guiding voice help them find their way.

A series of surprise discoveries lead the Hollisters on a hunt for Bobby on shore. Other adventures provide good times along the way. But there are false clues and disappointments before the Hollisters find Bobby, solve the mystery of the tagged fish, and bring happiness to an old man, Bobby and his mother.

The Hollister family comes alive in the seventy action-packed illustrations so that readers have a feeling of really sharing in the lively adventures and good times of this lovable and interesting family.

From the dust jacket