Hana Yori Dango Episode 21

Makino Tsukushi, a girl who comes from a poor family, just wants to get through her two last years at Eitoku Gakuen quietly. But once she makes herself known by standing up for her friend to the F4, the four most popular, powerful, and rich boys at the school, she gets the red card: F4's way of a "Declaration of War." But when she doesn't let herself be beaten by them and is starting to fall for one of the F4, Hanazawa Rui, she starts to see that there is more than meets the eye... (Source: ANN)