GTO. Cool Teacher Onizuka. Book 6

The golden heart of Onizuka helped him find a common language with all the students in his class... Or almost all of them. It's time to sort out the strange relationship between Miyabi and Kanazaki – former friends turned foes. Miyabi reveals Kanazaki's secret, and Kanazaki retaliates by wanting to publish footage from a hidden camera in Miyabi's room. The students try to hack the website where the video is supposed to appear, but then Kanazaki herself disappears...