It is the first day of April in the town of Green Lawn, and everyone is fully ready for a good, hearty laugh. When the friendly local bookstore owner, Mr. Paskey, pulls a hilarious April Fools' Day prank on Dink, Josh, and Ruth Rose, the kids immediately start plotting a clever joke to get him back. But before they can launch their funny, harmless revenge, the local bookstore is actually robbed by a real thief, and this terrible crime is definitely no joke. The kids have to put their silly prank on hold and get right to work on the serious case. Join the investigation and help the smart team sort through the messy clues left behind in the quiet book aisles. You will need to keep a sharp eye out to catch the real crook before this wacky, unpredictable holiday turns into a total disaster.