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".

The group is searching for mew aqua around a large rock formation in the forest when the girls and Masaya get separated. Something strange begins happening and everyone transforms. Masaya transforms into the Blue Knight, but falls from the rock and returns to normal. Kish confronts him and reveals that he cannot maintain his Blue Knight form if he is not protecting Ichigo. The alien moves to kill Masaya, but Mew Ichigo transports and appears between them. Masaya is knocked unconscious as Kish tries to kill Ichigo. This triggers Masaya's transformation, but his powers go out of control due to his rage at Kish. The other Mew Mews teleport to Mew Ichigo just in time to put up a shield around her as the rock explodes from the Blue Knight's power. Masaya returns to normal, seemingly unharmed. Kish tells Pie and Tart that the Blue Knight is the one who can save them.