I definetly don't understand what's going on... what is JTV? dammit...#－.－)

JTV is a company (not sure but I think it's a major broadcasting network of sorts) that Chiba-san is in charge of. He is the man that Murai slept with in order to rise himself to the top. The only people who knew about Murai sleeping with Chiba-san so far were his mother, Kaneko-san and Kato, although Kato found out on his own through observations. Kato wanted to tell Iwaki, but didn't want to hurt him, but when Iwaki realized that not only did JTV give a drama position to Murai, but he was also put into a very important movie with a very important role, Iwaki figured it out and, I'm guessing based on the last page, is very devastated. No rookie with Murai's unexperienced level of acting would land two important acting gigs back to back, so that's how Iwaki realized that Murai followed his mother's (that bitch) advice and slept with the head of JTV, Chiba.

Thanks :)