Have A Nice Stay In Gehenna! (Dropped)

Rin sees himself wandering around in a strange place. He meets his demon siblings and is put in their care. Yukio wakes up from a coma only to find that Rin has disappeared and is in Gehenna. What will happen to Rin and can Yukio help Rin escape before Rin says he doesn't want to leave Gehenna to go back to Assiah? (I'm no good at summaries. Btw, sorry about the bad summary)