Check the author's work. There's a full story of that one shot called Never Days.
Can u send me the link please ヾ(☆▽☆)
Whoops, sorry I was mistaken.It's still a one shot but here's the link anyway if it ever updates again (unlikely.)
http://www.mangago.zone/read-manga/never_days/
Still, thank you!! I at least can update it as already read and be able to reread it whenever! Thank uuuuu(▰˘◡˘▰)
The last one shot? Why? I feel like crying now i even forgot the main story until i read the extra ╥﹏╥