The kids in Room 3B are holding a Sharing and Caring Tag Sale to earn money for charity. Song Lee and Ida are selling friendship bracelets, Doug is selling books, and Sid is selling delicious, fresh-baked chocolate chip cookies. But something else is on Harry's mind: his grandmother is having money trouble, and Harry wants to help. So he comes up with a plan to raise money for her. The problem is that Harry doesn't realize his plan involves stealing from the class's charity collection! How can Doug stop his friend from becoming a horrible thief? Could the answer come from one of Sid's delicious cookies?


3B班的小朋友們要舉行一場名為「分享關懷」的二手拍賣會來為慈善募款。李頌和艾達要賣友誼手環、道格要賣書、席德則是要賣剛烤好的美味巧克力碎片餅乾，可是亨利心裡卻在想著其他的事：亨利的奶奶現在經濟困難，亨利想要幫忙，於是他想到一個幫奶奶募款的計畫，問題是亨利並不瞭解他的計畫裡包含竊取班上的慈善募款！道格要怎麼阻止他的朋友亨利變成糟糕透頂的小偷呢？答案會出現在席德的美味餅乾裡嗎？