Jiisan Baasan Wakagaeru

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.