Fenton Hardy, the famous private detective and father of the Hardy Boys, asks his sons to help him with his latest case involving the illegal drug trade. Hardy sends Frank and Joe to a house on the cliff, whose location offers an excellent vantage point to watch for smugglers. The Hardy Boys are tricked into going inside the house by cries for help and find themselves trapped for a short time in the attic, meanwhile, their telescope and motorcycles...

Teenage detectives Frank and Joe Hardy investigate a case of counterfeiting.

The adventures of the four Alden children as they spend a summer vacation on their very own island, purchased by Grandfather's father years ago.

A young Canadian visitor helps the Alden family solve a mystery involving a lost coin collection.

The town's ten-year-old walking encyclopedia again solves ten neighborhood mysteries. The final solutions to the cases are at the back of the book, giving the reader a chance to compare his skill to that of Encyclopedia Brown.

Six children help solve the mystery of a missing spyglass that has kept two brothers feuding for years.

The Aldens' dog, Watch, comes across a mysterious box with a note inside, a box that is part of a game called Geocaching. Henry, Jessie, Violet, and Benny join the game but soon suspect one of the members of the geocaching club is a thief.

The Alden children, isolated in a storm at a small bus station, are led into a mystery centering on a polluted river.

"The winter sports season is here, and the Aldens are excited about all the snow activities--especially snowboarding. But soon they find themselves in the middle of a mystery surrounding a star athlete and a stolen snowboard"--

Assisted by her cat Max and her friend Cash, Minnie tries to find Mary Moon, a valuable racing pigeon that has disappeared just before a big race.