Ep. 1: Fuuka Saitou recalls a childhood promise to marry her brother Hikaru while navigating school rumors.

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Fuuka Saitou honors a promise made two years ago to marry her brother Hikaru Saitou upon reaching adulthood. Her high school popularity draws the attention of Natsu, but she is shocked to learn a specific nickname from Rin Fujisaki. Fuuka attempts to care for Hikaru by consuming milk and a banana, though her behavior makes him uncomfortable. She also bakes a cake for him for the first time, further complicating their sibling dynamic as she pursues her romantic intentions.