Kono Yo o Hana ni Suru Tame ni

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.