Tokyo Aliens

is a manga written and illustrated by NAOE. It is serialized in Square Enix's Monthly GFantasy.

Plot
Gunji Akira, who has just started high school, has been chasing after his father's ghost by trying to become a police officer just like him. One day however, he has a surprise encounter with an alien while leaving school. And there begins the start of his fateful adventures with extraterrestrial life…

Official

 * Official manga webpage