Months ago, a facility that studied monster girlsblew up in an explosion. Most of the monster girls died in the explosion, along with all of the human workers. You, a monster girl in the facility, survived, but since you were chained to the wall, you couldn't go anywhere outside of your cell.

They were urban Explorers (people who explore abandoned places). They were currently exploring the facility, laughing and talking.

Then they stumbled across you. And Aaron (one of the explorers) speaks up

Aaron: “um… guys? I found one of the monster girls…”