During a rooftop lunch together on a beautiful day, Nanako asks Eiji if he remembers the day they met, and the final episode proceeds to re-tell that reliably adorable story. It was indeed their mutual love of senryuu poetry that brought them together, as they meet, and are the only two young people, at a poetry workshop around Christmas.
When Eiji comes in late with a head of steam, everyone is content to take him at face value—as a thug. Nanako, on the other hand, claps when he quickly comes up with a senryuu asking Santa to stop his dad from smoking so much. They exchange pleasantries outside, but Eiji warns Nanako not to get too close lest people speak ill of her.
But Nanako isn’t interested in what others think of Eiji, she feels she’s connected with him on a major level, and can’t stop thinking about him. They don’t see each other at a workshop again, but begin exchanging senryuu on a public bulletin board, essentially becoming senryuu pen pals. Nanako arranges for them to meet up when the cherry blossoms bloom in Nishi Park—truly a poetic setting for their next rendezvous.
When she sees no reply on the board on the day they’re to meet up, Nanako asks around, but no one knows what has become of Eiji. She starts running in a tearful panic, worried she let the one person she connected to most slip through her fingers. But she had no reason to fret: Eiji shows up under the same cherry blossom she envisioned for their meeting.
Back in the present, as Eiji lazes in the sun and Nanako sits beside him, she simply casts a big, beaming smile at him, and the two of them couldn’t look more content, regardless of whatever relationship boxes Amane thinks they still need to check off. It’s a pleasant, cozy end to a feel-good series about two very different people with the same very specific hobby.