Ryosangata Riko: Saigo no Puramo Joshi no Jinsei Kumitate Ki

Komukai Riko is the family's second daughter, with an elder sister who is sturdy and a younger sister who is more free-spirited. Riko was working briefly in Tokyo when she returned to her parent's residence after her grandfather died.
While rummaging through her stuff on the roof where the family has gathered for the first time in four years, Riko comes across a half-completed plastic model. Riko was guided by Yassan to the Yajima model shop where her grandfather used to go, and she decided to make her first plastic model.
Riko, feeling that she knows a little more about her grandfather and family, resolves to spend the summer at her parent's house so she can do what her grandfather regrets.
(source : mydramalist)