The Tower Mansion has been robbed and the father of a friend isunder suspicion. The boys discover the real thief and track down theloot.

The boys crack a smuggling ring operating out of an old house onthe cliffs of Barmet Bay and rescue their captured father in theprocess.

Counterfeit money is circulating in Bayport!The boys trackdown the counterfeiting gang at their base in an old mill.

Chet and Biff are kidnapped and held for ransom by a gang ofbank robbers, who mistakenly believe they are holding Frank and Joe.

The boys head to Montana to track down a buried stash of gold.

The boys clear their friend's name and defeat a gang of carthieves operating in the Shore Road area by using a Trojan Horsemaneuver.

A woman asks the boys to track down her missing brother, whomthey discover is suffering from amnesia and living as a hermit in thecaves near Bayport.

The boys solve the mystery of a missing stamp collection whilecamping on an island in Barmet Bay during their Christmas vacation.

The boys are framed for air-mail theft and must solve the caseto clear their names.

Joe is kidnapped as the clock strikes midnight; after hisrescue, the boys travel to New York in pursuit of a ring of diamondsmugglers.

The boys discover how and why Raymond Dalrymple is receivingthreatening notes in a secret room of the old Purdy mansion.

The boys crack a human trafficking ring smuggling illegalChinese immigrants into America.

The boys go to Mexico with their father in search of a missingwitness in a court case involving fradulent oil stocks.

In the course of solving a robbery for which they were unjustlyaccused, the boys go to the South and end a long-standing family feud,solving a case for their father in the process.

The boys track down a stolen racehorse and save Bayport fromdestruction by the madman Vilnoff.

The boys foil the "Eye Syndicate", a gang run by the phony eyesurgeon Doc Grafton.

While searching for a million dollars' worth of treasure in asunken ship, the boys must deal with unscrupulous diver Gus Kuntz.

The boys go undercover on a pirate ship to defeat the "TwistedClaw" smugglers and reveal their island stronghold.

The boys help to bring a gang of bank robbers to justice.

The boys foil a foreign spy training operation using the"Flying Express" train.

​

While working at an experimental farm, the boys investigate thedisappearance of valuable silkworms and the theft of government buildingmaterials.

After receiving an amnesiac's warning about the "Curse of theCaribbees," the boys foil a gang that is stealing valuable coins andmelting them down for counterfeit.

​