While Ichigo Momomiya is on her first date with Masaya Aoyama, she is bathed in a strange light and sees herself being merged with a cat. Afterwards, she begins to display cat-like behaviors. The next day, Ichigo follows Masaya into a park, where a strange jellyfish-like creature takes over a rat's body, turning it into a monster. Ryou Shirogane saves Ichigo and gives her a pendant allowing her to transform into Mew Ichigo. With her new powers, she defeats the monster, turning it back into a normal rat. Afterwards, Ryou refuses to explain what just occurred, so the newly arrived Keiichiro Akasaka offers to do so instead.

Masaya takes Ichigo to Inohara Park to show her a large cherry tree that is unusually blooming out of season. The next day, Keiichiro discovers that five cherry trees have been infected by the aliens explaining the early blooming. The Mew Mews set out to destroy them simultaneously, or the trees will release a poison dangerous to Tokyo. Mew Ichigo takes the tree in Inohara Park, where Kish waits for her. A fight keeps Ichigo from attacking the tree, and it begins releasing its poison. Ichigo jumps into the tree and successfully destroys it. After Kish leaves, Mew Ichigo finds Masaya standing behind her after he called out "Ichigo".