Sakura's grade goes on a field trip to pick strawberries. Sakura and Tomoyo bump into Yukito and Toya who are working part-time at the strawberry field. On the way to the greenhouse, Syaoran senses something from the storehouse, but Meilin pushes him along. The class enters the greenhouse and begins picking strawberries. Sakura hears the door to the storehouse will not open, but when she and Tomoyo go to investigate, they find it open. Syaoran and Meilin come into the storehouse, and Syaoran says that he feels a strange presence. The door suddenly closes and locks them inside. Syaoran informs the group that it it the Lock card that has trapped them. After Rika, Naoko, and Chiharu come to the storehouse, they go look for Ms. Mizuki and tell Toya and Yukito. While looking for a key to unlock the door, Sakura sees Ms. Mizuki through the window, who gives her a hint, but Ms. Mizuki then disappears. Sakura realizes that Ms. Mizuki was trying to tell her to use her key. The Lock card shows its true form when Sakura tries to put her key into the lock. Syaoran seals the exits and Sakura quickly seals the Lock card before it can get into the keyhole. Toya, Yukito, Rika, and Naoko come into the messy storehouse, now that the Lock card has been captured. Sakura and the others clean up the storehouse together. Sakura's group learns how to make and bakes desserts with strawberries. After the desserts are made, Sakura brings a piece to Toya and Yukito.