Grandpa and Grandma Turn Young Again - Season 1 Episode 4 Grandpa and Grandma and the Culture Festival
Overview: 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.