Sayaka, a researcher at a rural Japanese facility, becomes captivated when Linea emerges from a decade-long dormancy in a sealed capsule. Her growing obsession drives her to abandon her relationship with Misuzu and forge a profound emotional and physical bond with Linea. During a moment of intimacy, she uncovers Linea’s superhuman capabilities, far exceeding ordinary human limits.

The sudden activation of a second capsule shortly after Linea’s awakening plunges Sayaka, Linea, and their colleagues into grave danger. As tensions rise, Sayaka’s choices become the catalyst for the escalating conflict surrounding the mysterious capsules, directly triggering the life-threatening risks confronting the group. Her decisions shape the trajectory of the crisis, though her personal history and fate beyond these events remain unexplored.