The Alden children help their favorite Internet celebrity, Walter the cat, when he inherits millions from his owner and rumors begin to fly about his famous tricks being fake.

The Alden siblings investigate an old building in Silver City where unlucky events keep happening.

"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"--

"A talented young soccer player in Greenfield is given the honor of being a child mascot at an international soccer tournament in Brazil, but when an anonymous letter insists that she doesn't deserve to go, the Aldens investigate"--

"One day in the park, the Aldens' dog, Watch, comes across a mysterious box with a note inside. 'Congratulations!' the note says. 'You've found it!' The box is part of a game called Geocaching. Soon, Henry, Jessie, Violet, and Benny are searching all over town for hidden boxes and making friends with other kids in the geocaching club. But is one of the club members a thief?" -- p. [4] of cover.

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 are at Wildcat Crossing, a recreated frontier town full of cowboy fun. But when horses disappear and other pranks threaten to ruin the Wild West show, the Boxcar Children must find out who's the varmint causing all the trouble"--

The Aldens investigate when the arrival of several suspicious characters in Greenfield coincides with a mystery involving a popular boy actor.

When a local antique shop owner loses his memory after an accident, the Alden siblings help piece together the man's past to uncover who is holding a grudge against him.

During a trip to Oregon, the Aldens are astonished when Watch discovers a backpack filled with valuables, a finding that compels them to learn what happened and return the backpack to its rightful owner.