Grandpa Hearts Futaba.Sakurai accidentally sends a misleading photograph of Igarashi and Takeda to Igarashi's grandfather. Igarashi goes shopping for her own birthday present, causing Takeda to realize their birthdays are the same day, so they buy each other flowers. Igarashi's grandfather then arrives and, despite having similar personalities, butts heads with Takeda over who has the right to tousle Igarashi's hair. Despite trying to avoid each other, Grandpa and Takeda have a lot of hobbies in common, repeatedly bumping into each other and competing childishly at fishing, baseball and even litter picking, gaining a grudging respect for each other...