In Giantess Spa - Investigation, your character's name is Lucas, and you're a detective in the city you grew up in. You are investigating the mysterious disappearances of several men. It seems almost as if these guys vanished out of thin air, and you need to get to the bottom of it. As you move forward in your investigation, you discover a cruel, evil underground of dominating women in a Femdom society. The guys haven't disappeared; they've been kidnapped and are the playthings of these sexually sick and twisted women.