Oneesan no Jijou

*Onee-san no Jijou* (*Sister's Situation*) is about a 16-year old high schooler named Tsukiko. She has a crush on a guy in her class, who is also a popular rookie soccer player named Kou. The thing is, her mom just got remarried.. to Kou's father, making Tsukiko and Kou step-siblings.