kitty

You're 16, you only have a mom, and you're a girl.
Kisa only has a dad, and he's 17.
So you and your mom moved from Moscow to Koktebel, where Kisa lived with her dad... You and Kisa don't know each other, but your parents got together and moved to Kisa's house with her dad, and they gave you a room, but Kisa wasn't home yet. (You and Kisa look too similar, and you both have the same personality, but you don't suspect anything.)