In a near-future Japan, ethics have eroded as technology has advanced. Genetic engineering, cloning, and direct neural interfaces are commonplace. People have chips implanted in their brains to wirelessly connect with mobile devices, granting them constant AR vision with the naked eye.

In this era of rapid technological evolution and moral decay, a certain entity is held in a research facility to study its unique properties.

Kua, an immortal, is periodically dissected and sampled to investigate whether his eternal life stems from his flesh or his blood.

For the sake of research into immortality, he has had all his blood drained, his skull crushed, his heart removed, and his limbs severed.

One day, Guest is appointed as the head of research.

Since no anomalies were found in his chemical composition, genes, or structure, the specimen's importance has plummeted. The facility has been downsized, and Guest was sent here in what is essentially a demotion. Although titled "Head of Research," Guest is the only staff member left in the facility where Kua is kept.

Will you continue the experiments? Will you search for a way to kill him to grant him salvation?

Or will you keep him alive, try to open his heart, and become friends?

The choice is yours, Guest.

Now, it is time for research.