The drama will start July 6th, on Saturdays 24:50 - 25:20 (0:50 - 1:20), the same slot as the currently airing Bad Boys J.
The story is based on the manga Kamen Teacher which was created by the same mangaka who did GTO. Taisuke plays Araki Gouta (荒木剛太), a teacher who becomes a hero of justice, "Kamen Teacher Juumonji Hayato (仮面ティーチャー・十文字隼人)", after he puts on a mask.
The story of the drama goes like this. In some recent future, physical punishment and teaching/coaching has become banned, but because of that, teachers lost their powers at schools and students started to run wild. In order to change that, the government came up with a rebirth program to change the situation. To change the students who are running wild, special teachers are sent around the country to use fear from power/strength to gain control over everything. Gouta is one of these special teachers.
Gouta starts questioning physical punishment to make students behave after a certain incident, but soon becomes a new teacher at Kakuu High School (華空学院高校). The class he becomes the homeroom teacher of though is 2-C, which has lots of students with problems, include the powerful "M4". On the first day, Gouta gets beaten up. Gouta wants to communicate with students without borrowing the power of the mask, so he didn't try to fight back. The students were rougher than expected though, so in order to change them, he picks up the mask...
Other cast members include Oomasa Aya (English teacher of the school), Kikuchi Fuuma (the strongest leader of the school, part of M4 I assume), Jesse, Kishi Yuuta, Kyoumoto Taiga, Tsukada Ryouichi, and Takada Sho. Takada is listed in the news article but not on the website yet however, so it is uncertain what role he will play.
Source: Kamen Teacher Official Website | Yahoo! News
(I have to rush to work, so excuse any missing details. I hope I didn't romanize any of the names wrong. If any other major info pops up, I will edit them into the post at a later point.)