Based on the erotic game by Studio Polaris.

It's another day on the job for Takeshi Saito. He recently started working as a security guard for a high-tech amisement park called Fantasien. However, a bad day at work quickly spirals into a nightmarish maze of murder and mystery. It starts when Saito accidentally breaks a guidance display at work. Saito and Tamami are called into the office of Ms. Amano, his sexy boss. Makoto Kashiwara is sent out to repair the display. However, Kashiwara stumbles across a dark secret...

(Source: Anime News Network)