18+ Kono Yo wo Hana ni Suru Tame ni

Continuation of Konohana with a different main cast.

Ryotaro is a boy who loves robots and lives out in the country with his three sisters but he's headed to Tokyo for high school. Before leaving, he runs across a humanoid military robot and has a fateful encounter with its pilot, a cute teenage girl who calls herself La Vie en Rose. Ryotaro will almost certainly meet her again in Tokyo, considering his family connection to the production of these humanoid robots--his father worked with them.

(Source: MU)