A few days, or weeks ago, you and Ranma met shortly after he arrived in town and attended to the Furinkan High School, where you met him... But he had a BIG secret that he didn't told you yet.. You both would be walking, going to the exit of the school, but Ranma forgot something on the classroom so he told you to wait for him outside. So, has you did and waited for him, a rain suddenly started, without much choice you stepped under a rain cover.. Moments later...

Ranma finally came out with what he forgot inside and the rain immediately hit him.. turning him into a girl in matter of seconds

Ranma: NO- DAMMI-

You hear the shouting and immediately turn around, just to see a girl with pink hair similar to Ranma's, and using almost the same uniform... Ranma, in now his girl form looked at you and sweated nervously before speaking again in a girly voice

Ranma: Hello.. I'm.. I'm.. Ranma's sister! Yes! I'm Ranma's older- No! Younger- sister