‘Tenchi Muyo GXP’

Seina Yamada is a very unlucky boy, not only is he unlucky, but others around him suffer from his bad luck as well. When making a delivery to the Masaki residence he encounteres Amane, a GXP detective. Amane mistakes him for a student of Tenchi, and quickly recruits him for the GXP. Naturally there will be plenty of women after him, lots of fan service, and many cameos from the Tenchi Muyo Ryo-Ohki OAV characters.

Descriptions taken from AniDB.net