20th Century Boys Vol 13

From the VIZ Media edition

Chino is a teen looking for love, but instead of finding a boyfriend, she gets stuck with Hyou, a feral child her father brought home from a jungle. Having grown up in the wild Hyou doesn't have any idea how to live a human life. Now Chino has to take care of him and guide him as he tries to adapt to city life.

Source: Anime News Network Encyclopedia