[Original Manga](https://mechacomic.jp/books/180411)

University student Mio can't let go of her lingering feelings for her ex-boyfriend, Atsushi. One day, it's not Atsushi who shows up at Mio's house... but his younger brother, Taishi, who looks exactly like Atsushi. Mio tries to see the resemblance of Atsushi in Taishi, and falls into self-loathing. Taishi kindly accepts her, and then confesses something... I want to take another step into love... A pure and heartbreaking love story between a complicated me and a straightforward you. (Source: Hakusensha, translated) *Note: Includes three extra chapters.*

The newlyweds are touring the caves of Borneo.They decide to visit Mt. Muru wich has one of the largest caves in the world. Meanwhile, the husband disappeared and the husband who came back...