S01E36 — Shirogane's Past: The Secret of the Mew Mews' Birth!

Ichigo tries to talk to Ryou about the problems caused by her cat genes, but he ignores her. On the way to school, Ichigo changes into a cat again and gets in trouble, but is saved by Alto who also kisses her to change her back to normal. Despite his struggling, Ichigo picks him up and is shocked when he suddenly changes into Ryou. After school, she goes to the café where Keiichiro tells her the history of the Mew Project, which was started by Ryou's father. After his parents were killed by an ancient chimera anima, Ryou decided to continue his father's research. Wanting to be sure the merging process was safe, he tested it by merging himself with cat genes. This gave him the ability to change into a cat at will, but only for 10 minutes at a time or he will remain a cat permanently. Ichigo promises to do her best as a Mew Mew.