"We still don't know the name of the flower we saw that day" tells the story of the members of "Ultra Peaceful Busters" in order to realize the death of a deceased member. Wish, the story of reuniting again, because the protagonist in the story, Meizi, suddenly appeared in front of Renta. This made Renta, who had been reluctant to go to high school, realize that he had to take this step. In the movie, Meizi got rid of Renta to realize her wish, so Renta began to send text messages to the other 5 people from the beginning
Meiko was a member of the 6-person group "Super Peace Busters" in elementary school, but later because of Meiko's death. The other five people began to separate, and many years later, taking the reappearance of Meizi as an opportunity. These five people are about to reunite again, walk the path of the past again, and recall the truth of the events of the year. The five people have gone through the spiritual salvation process from complaining to mutual understanding, and finally they are able to cross this hurdle in their hearts and start their own next steps. Yiyishengsheng, Naruko, Ji, Zhilizi and Tie Dao are also working hard to realize Meiko's wish.