The Secret of the Old Mill is an enthralling mystery novel from the beloved Hardy Boys series, penned by Franklin W. Dixon. In this captivating tale, brothers Frank and Joe Hardy, amateur sleuths with a knack for solving crimes, find themselves embroiled in a perplexing case that leads them deep into the heart of an old mill shrouded in secrecy. The adventure begins when the Hardy boys stumble upon a cryptic message hidden in a hollow tree, hinting...

The Hardy boys and their father solve a mystery involving inexplicable crashes of highspeed race cars being used to test an experimental turbine motor.

The Hardy boys embark on another puzzling mystery when they try to discover who is stealing rare collections of ancient pirate treasure and smuggling them out of the United States.

After the new hydrofoil they are guarding is stolen, the Hardy boys face frequent danger in solving a mystery involving criminals who operate by signs of the zodiac.

The Hardy boys and two friends take a camping trip to the Rocky Mountains in an attempt to locate a gang of credit-card counterfeiters.

When their peregrine falcon brings down a homing pigeon carrying rubies, the Hardy brothers find themselves involved with kidnappers.

In solving the mystery of two medallions missing from an inherited curio collection, the Hardys wind up in a desolate area of Guatemala at the mercy of dangerous thugs.

Hired to locate an old Spanish cannon, the Hardy brothers uncover an even greater treasure after perilous underwater adventures.

When they journey to Alaska to help a friend who feels his life is in danger, the Hardy brothers find their own lives threatened.