Sakura's class is on a field trip to the aquarium. During the penguin show, something catches the trainer's leg and a penguin and pulls them into the water, but they are saved by Sakura's brother, Toya, who is working part-time there. At school, Tomoyo gives Sakura and Kero mobile phones and on the way home, Sakura bumps into Yukito who invites her on a casual "date" to the aquarium. While they are eating, the Watery Card attempts to drown Sakura. For the first time, Sakura has to formulate a plan to capture a card.