Rasen Kairou
Japanese title: 螺旋回廊
Type: OVA
Source: Visual novel
Episodes: 2
Status: Finished Airing
Aired: Jun 28, 2002 to Sep 27, 2002
Duration: 27 min per ep
Rating: Rx - Hentai
Studios: Studio Kyuuma
Producers: Pink Pineapple
Genres: Hentai

Saeki is an assistant professor at the university, who happened to find a unique site while surfing the net. The site displays abducted woman who have been enslaved for the purpose of fulfilling the desires of EDEN's visitors. The woman are used as tools of pleasure, they are humiliated and abused in all manor imaginable. Has Saeki gotten himself in too deep and how will he fair when EDEN's newest victim is a familiar student from his university. Will he find himself unable to turn away from the darkness that is EDEN? 
 
(Source: AniDB)