Yu Yu Hakusho, Volume 16: Into the Demon Plane!!

Itsuki locks the others away in a separate dimension so Yusuke and Sensui can fight undisturbed. Under intense pressure, Sensui's real personality, suppressed for so long, starts to come out. Then Koenma shows up and things really start to get hot, forcing Yusuke to resort to desperate measures to draw their enemies out.Kuwabara and the rest of the crew escape Itsuki's clutches and plunge into the Demon Plane after Sensui. Meanwhile, the Underworld special defense force goes looking for Yusuke. What secret do they know about Yusuke that is enough to sign his death warrant?