this one is interesting, because the wedding invitation has to be for the girl Bun-chan used to like, but there's two girls here! How awful haha, I do wonder though if this is going to be more than just a story of an unrequited love and have Bun-chan get lucky with the other girl in the end.
Right now we have Mahiro who Bun-chan has known for a long time, and Kiko-senpai who is someone that frustrates Bun-chan, and while I think Mahiro is the girl Bun-chan liked and who sent the wedding invitation in the present, Kiko sure is also here and I wonder how that relationship is going to develop/be revealed to stand in the present by the end of this prequel.