Kaoru is he dad's girlfriend. Fiancée? She's already moved in anyway.
She's trying to be nice to Miyo, but Miyo would rather be left alone.
Miyo is in middle school. That's a hard age to pick up a stepmother.
Miyo has her own plans, which involve the cat mask.
When she puts it on, she transforms into a cat, which Hinode has adopted and named Taro.
The only problem is that the mask salesman is following her. He'd like her human face in exchange.