Shouzou and Ine, an old married couple, are known to everyone as a pair of lovebirds. One day, they wake up to find they look like their younger selves! When Mino, their granddaughter, sees them, she's shocked by their transformation, and she's not alone!

Shouzou and Ine often have visitors dropping by. One day, their granddaughter, Shiori, comes to their house after a fight with her father, Takahiro. He's a doctor. Shiori aims to follow in his footsteps, but she's worried about her grades and friendships.

Ever since Shouzou and Ine turned young again, they've had dreams of a mysterious hourglass. One night, Shouzou has the dream again and something unexpected happens. The next morning, when he wakes, his body has returned to that of an old man.

At Mino's invitation, Shouzou and Ine decide to go to the culture festival at her school. Once there, an accident causes Ine to have to change clothes. When she puts on a sailor-style school uniform, she reverts to mannerisms she used in her school days.

Ine's memories have turned young again. She is now who she was before she met Shouzou. Even amidst her confusion at seemingly having traveled into the future, she is curious as to why she married Shouzou and offers him a certain suggestion.

As their long-awaited honeymoon approaches, Shouzou and Ine plan the details of their trip. They recruit Shouta to be their guide, and Mino decides to go with them, too. Once they arrive in Tokyo, Shouzou and Ine go to see their daughter Akemi.

Shouzou, Ine, and the others arrive at a lovely inn in Atami. After some sightseeing and delicious food, it's time for bed. The plan was for the men and women to sleep in separate rooms, but Mino wants Shouzou and Ine to have time alone together.

Shiori meets a medical student named Satoshi at the university library. He is researching old legends from the area of people turning young again. He confides in Shiori, saying that something unbelievable has happened to his grandparents.

It's the day of a summer festival at a local jinja. Ine drsses Mino a cute yukata. Mino makes sure that Ine wears one, too. Ine looks forward to walking around the festival with Shouzou that night, but Shouzou has to spend time with the neighbors.

Daily life continues for Shouzou and Ine. Mino convinces them to try their hand at Halloween costumes. Shouzou patrols the orchard. A rainy day brings back old memories. Ine does a few small things that make a big difference in other peoples' lives.

As the year draws to a close, the Saitou family prepares for their New Year's celebrations, which keeps Shouzou and Ine very busy. On the last day of the year, the whole family, including Ine's older sister, Tsuru, gathers at Shouzou and Ine's house.