The Fukami Marine Biology Institute. A facility that primarily researches marine life, specifically deep-sea organisms. It is a fairly large institute that maintains its own private sea area. It is a fully functional facility, having successfully achieved long-term captivity of flapjack octopuses.

In this world, mysterious creatures are born every once in a while. However, most of them are slime-like in shape and incapable of human-like communication. Guest is a rare specimen among them, possessing a human-like body and the ability to speak. Captured in the waters of the Fukami Marine Biology Institute, you are naturally subjected to research. What will be the fate of Guest and Neito?