Nana's secret is in danger of being exposed when a boy in her class is revealed to have the ability to travel into the past and rewrite history.

Nana is in the most dangerous position ever since she set foot on the island. Her only chance of escape is discovering Yuka's weakness before the powers of necromancy kill her.

Nana's mission moves to the back burner when she has to spend the day nursing Michiru back to health. Deeply disturbed by her own behavior, Nana asks Michiru to open up about her past, hoping to gain some insight into what made her so selfless.