18if

18if is an anime series produced by Gonzo. It began airing on July 7, 2017.

It is part of the media franchise The Art of 18, which also includes a smartphone game by Mobcast titled 18: Kimi to Tsunagaru Puzzle (【18】キミト ツナガル パズル, 18: Kimi to Tsunagaru Pazuru).

Plot
Haruto Tsukishiro wakes up in a dream world dominated by strange and powerful entities called "Witches". To survive, he gets the assistance of research professor Katsumi Kanzaki and a mysterious white-haired girl called "Lily". With their help, Haruto must outsmart the witches and find a way to return to the real world.

Other Sources

 * MyAnimeList