beforePX-14

2 years before the previous episode.

Elvira, who has not yet under the influence of hypnosis, falls into the hands of Shirakawa, a gym teacher, while her husband, president of the school, is on a long business trip.
This time, it is triggered by a tasteless and odorless liquid, PX-12, a previous-generation drug of PX-14.

[From DLsite English]