Shonentachi (2019)

At a boy prison in 2012, the prisoners fight each other all the time. A new boy prisoner enters the prison. He does not talk to anyone. He is always alone and he often writes in a diary. The new boy prisoner meets another prisoner he can trust and they becomes friends. Meanwhile, a new prison governor arrives at the prison. He uses violence to govern the prison. The boy prisoners can't tolerate the new prison governor and they set up a plan.