With her dislike of Yuzu and Mei's relationship, Matsuri uses the secret photo she took at the shopping mall to blackmail Mei into fooling around with text-pal on Christmas. Meanwhile, Yuzu knows nothing of this and struggles to bake a cake for her first Christmas together with Mei. While her excitement builds, Mei comes home and breaks the news that she won't be able to join their Christmas Party due to student council work...
It's fine. Yuzu-chan's 
my big sister after all.
Das ist in Ordnung.
No pasa nada.
No pasa nada.
Mais si.
Non preoccuparti.
Tudo bem, Yuzu-chan é minha
irmã mais velha mesmo.
Всё будет хорошо. Она
всё-таки моя сестрёнка.