Cheerful Amnesia manga volume 4 features story and art by Tamamushi Oku.

Arisa and Mari have finally decided to get married! The two are in a better position than ever to prepare for the ceremony now that they may know the cause of Arisa's amnesia, except…Mari still hasn't told her family about their relationship. And so, amidst all the wedding planning, Mari and Arisa go to greet Mari's parents and announce their intentions—but will the pair be able to get through to them?