18+ Destiny Lovers

Takuma Misato, who has a crush on a classmate, is suddenly kidnapped at the infirmary when he comes to have a second checkup. When he wakes up, he's strapped to a bed and forced to do "something" by a beautiful nurse he doesn't know! It's a mysterious hospital where men are locked in an isolation ward and managed by beautiful women! Where the hell are we? And what is the purpose of these beauties? And then the love game between a woman and a man with their lives on the line begins!

(Source: Kodansha, translated)