PENGUINDRUM GN VOL 04 (C: 0-1-1)

Twins Kanba and Shoma live with their terminally ill little sister, Himari. One day, they visit the aquarium, a place full of warm memories for Himari, but she suddenly falls ill - and dies! At that very moment, a voice cries out, 'Survival Tactic!' and Himari, wearing a penguin hat, comes back to life…?!