The missing chums

In Short

When high school chums Chet Morton and Biff Hooper vanish during a coastal storm, teenage brothers Frank and Joe Hardy set out in their motorboat to track them down. They trace the disappearance to Blacksnake Island, a treacherous, snake-infested hideout where a gang of extortionists holds the boys captive. Unfolding through midnight break-ins, boat chases, and perilous rescues, this third entry in the Hardy Boys series offers classic mid-century juvenile detective adventure driven by brotherly loyalty, quick thinking, and high-speed action on the water.

The Story

Teenage brothers Frank and Joe Hardy must stay home in Bayport while their friends Chet Morton and Biff Hooper take off on a week-long motorboat trip along the coast. Shortly after Chet and Biff set sail in Biff’s new boat, a violent storm breaks over the bay. Chet and Biff fail to return, and searchers find wreckage along the reefs. Tragic assumptions mount that the two boys drowned, but Frank and Joe refuse to give up hope.

Suspicion turns toward three suspicious men whom Frank and Joe previously spotted idling near the Morton farmhouse. Believing the men are linked to the disappearance, Frank and Joe assemble their circle of friends—Tony Prito, Phil Cohen, Jerry Gilroy, and "Slim" Robinson—and launch a search party in Tony’s boat, the Napoli, and their own craft, the Sleuth.

Following a trail of subtle clues, the Hardys steer their search toward Blacksnake Island, a rocky, desolate landmass surrounded by marshes infested with venomous snakes. Exploring the island, Frank and Joe discover a crude campsite and hear voices echoing among the crags. They spot the same three men from Bayport, who are working with an organized criminal syndicate.

Night falls, bringing another heavy storm. Frank and Joe discover a cave system where the gang is hiding. Sneaking inside while the criminals sleep, Frank frees Chet and Biff from their chains using keys he finds in the cavern. The rescue is disrupted when the gang awakens, resulting in a chaotic scuffle. Frank and Joe manage to escape in the Sleuth to summon help, but Chet and Biff take a wrong turn in the dark, become separated from the brothers, and are recaptured by the gangsters.

When Frank and Joe return to the island with Tony and their other chums, a tense standoff ensues. The criminal gang holds Chet and Biff for ransom, mistakenly believing they are the famous detective Fenton Hardy’s sons, before realizing they now have the actual Hardy boys in their sights as well. Through coordinated maneuvers on the water, the boys pin the criminals down on the island, preventing their escape until authorities can arrive.

Back in Bayport, the boys learn that their famous detective father, Fenton Hardy, has successfully dismantled the broader syndicate operating out West. With Chet and Biff safe, the Hardy household settles back into its lively rhythm, ready for the next adventure.

How It Unfolds

The journey begins Chet Morton and Biff Hooper depart on a week-long coastal motorboat cruise, leaving Frank and Joe Hardy behind due to family obligations. A sudden, violent storm strikes Barmet Bay shortly after their departure.

Disappearance and search When Chet and Biff fail to return, searchers discover sea wreckage, leading most townspeople to assume the boys drowned. Refusing to accept this, Frank and Joe launch a targeted search with their friends using the Napoli and the Sleuth.

Infiltrating Blacksnake Island The Hardy boys trace suspicions to Blacksnake Island, a desolate, snake-infested refuge. Exploring its barren rocks, they uncover a hidden campfire and confirm the presence of the suspicious trio from Bayport.

The cave rescue Under cover of a nighttime storm, Frank and Joe locate the gang's cave and find Chet and Biff chained to the rock walls. Frank picks the padlocks and unfastens their handcuffs while the guards sleep.

Separation and recapture An alarm sounds during the getaway, forcing the group to scatter in the dark. Frank and Joe reach their boat and back out under gunfire, but Chet and Biff take a wrong turn in the grove and are recaptured by the gangsters.

Final standoff and return Reuniting with their friends on the water, the boys blockade the island to keep the criminals trapped until help arrives. With the gang secured and Fenton Hardy returning victorious from his own case, the boys return home safely.

The People

• Frank Hardy: The tall, dark-haired sixteen-year-old older brother who leads the search effort. Driven by loyalty to his missing friends, he uses his sharp deductive skills and courage to navigate dangerous waters and covertly pick locks inside the enemy's lair.
• Joe Hardy: Frank’s fifteen-year-old brother, who is nimble, brave, and adept at physical action despite his shyness around girls. He wants to support his brother's leads, facing down heavy seas, armed criminals, and hand-to-hand scuffles on deck to see the rescue through.
• Chet Morton: The cheerful, practical-joking chum whose dream motorboat trip turns into a nightmare. Held in chains on a remote island, he maintains his resolve and fights fiercely against his captors during escape attempts.
• Biff Hooper: Chet’s reliable friend and driver of the motorboat Envoy. He seeks adventure on his father's new craft, but ends up captive alongside Chet, showing resilience when battling the gangsters on the beach.
• Aunt Gertrude: The boys' stern, sharp-tongued aunt who arrives with her cat to restore order. She opposes the boys' detective work, offering constant comedic friction and sharp reprimands.

In Its Own Voice

When Biff Hooper lost control of his father's new craft, the resulting lurch sent his friend sprawling across the deck:

Chet wavered precariously for a few seconds, finally losing his balance and sitting down heavily in a smear of grease at the bottom of the craft.

Unfazed by his brother's ease around female acquaintances, Joe Hardy struggled to conceal his shyness while visiting the Morton household:

"I thought you liked Iola Morton." "That's just the trouble--I do," answered Joe mysteriously, and Frank wisely forbore further inquiry.

Facing the terrifying reality of the remote island hideout, the boys realized the physical danger surrounding them:

Fascinated, the boys watched the ugly black head that projected above the surface, and they could see the long, sinuous body writhing beneath the water as the snake swam toward the fetid marsh.

What It's Really About

Beneath its swift nautical action and mystery plot, the story explores the bonds of adolescent brotherhood and self-reliance. It contrasts the comfortable, domestic security of Bayport—represented by family meals, school friendships, and the comical authority of Aunt Gertrude—with the unpredictable hazards of the wilderness. The narrative tests whether teenagers can rely on their own resourcefulness, courage, and loyalty when adult protection is entirely out of reach. It celebrates practical intelligence, teamwork, and cool-headedness under direct threat, showing that small acts of vigilance and devotion can overcome lawlessness and keep a group of friends unbroken.

Why Read It Today

This book offers a vivid window into early 20th-century juvenile fiction, delivering nostalgic, fast-paced storytelling centered on youthful independence. Readers who enjoy classic mystery, vintage technology, and straightforward adventure will appreciate the spirit of outdoor exploration—motorboats, campfires, coastal storms, and secret caves. The writing moves with energetic rhythm, emphasizing action and brotherhood over complex psychological interiority.

Modern readers should note the period-typical melodrama, straightforward characterizations, and occasionally improbable coincidences common to classic series fiction of the 1920s. However, the direct prose, high-stakes scenarios, and genuine affection among the core group of friends keep the narrative engaging. It leaves readers with a comforting sense of camaraderie and the enduring satisfaction of seeing teamwork and grit prevail against all odds.