Here's the summary from Wiki:
The drama is based on the popular manga of the same name by Nakajo Hisaya, which has already been dramatized in Taiwan. Horikita plays the protagonist Ashiya Mizuki, a Japanese girl in the U.S. who one day sees the young athlete Sano Izumi (Oguri) compete in the high jump on television. She begins to idolize him, and decides to move to Japan to attend the same school as him. However, Izumi goes to an all-boys school, so Mizuki disguises herself as a boy to achieve her dream of being with her idol.
Horikita Maki......... Ashiya Mizuki
Oguri Shun........... Sano Izumi
Ikuta Toma............Nakatsu Shuichi
Konno Mahiru.........Hara Akira
Kamikawa Takaya...Umeda Hokuto
Matsuda Seiko.........Tsubaki, the School Principal
Ukaji Takashi...........Sawatari
Kobayashi Susumu...Yoshioka
Okada Yoshinori.......Ashiya Shizuki
Daito Shunsuke .......Sano Shin
Shirota Yuu.............. Kagurazaka Makoto
Moriguchi Yoko.......... Nanba Io
Harada Natsuki.......... Tanabe Kanako

