Helen Plum Library

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

On a camping trip to Arizona with their grandfather, the Alden children search for a lost gold mine

The Aldens investigate when a new store called the Game Spot opens in town and the neighboring shops are robbed

The Boxcar children must track down an instrument thief in time to save Greenfield's music festival from disaster

The Aldens visit Grandfather's friend at the Ogopogo Retreat and aided by puzzling clues, embark on a treasure hunt to prevent the retreat from being sold

The Aldens investigate when an old wooden mask they have found is stolen

The Alden children stumble upon a mystery when they enter their dog, Watch, in a contest that could lead to fame and fortune, but where things keep going wrong

"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"--

The Alden children investigate various mix-ups at a zoo run by their grandfather's friend in an effort to save it not only from pranksters but also from the town council

While spending two days touring a zoo to see the baby animals, the four Alden children, aged six to fourteen, help catch an escaped monkey, participate in a photography contest, and investigate a missing camera