As the big sister in the family, Yuzu wants to take the lead in her relationship with Mei, but courting your step-sister is a huge challenge, so she turns to the research she's compiled in her secret notebook. With the help of her 'Fall in love with Mei and live happily ever after plan', Yuzu decides it's time to take the first step: invite Mei on a date. But before she can, Mei discovers the secret notebook....