Fourth comes for them, but Ninth arranges things so the other cops see what he's up to and arrest him. His diary shows what happens on his cases, so it's useless now.
He asks Ninth for one final favor, and pays with his life, destroying his own diary.
Amano and Gasai disappear.
Detective Nishijima inherits Fourth's case files. He learns about the diary holders.
He and Akise work out a plan to have their high school friends search for them, figuring they'll run if the police do the search.
They all get captured.