I am Sam (2007)

There are some offers that you just can't refuse. Jang Yi San (Yang Dong Geun) is a rookie teacher who is put in charge of a homeroom full of misfits and troublemakers, including Chae Moo Shin (T.O.P) and Yoo Eun Byul (Park Min Young). Eun Byul happens to be the daughter of Yoo Jae Gon (Park Joon Gyu), the head of a dangerous gangster organization. When Jae Gon realizes that Yi San can make his only daughter actually interested in studying, he makes the teacher an offer that he can't refuse: become Eun Byul's private tutor in exchange for one million won.