Happy☆Lesson Advance
Genres: Comedy, Romance
Type: TV, Episodes: 13
Aired: Jul 3, 2003 to Sep 28, 2003
Studio: Studio Hibari
Source: Manga
Rating: PG-13 - Teens 13 or older
Synopsis:
Hitotose Chitose is now living together with his 5 teachers as his mothers when a mysterious girl appears and becomes their neighbor which turns out that that person is Nagatsuki Kuron who wants Mu-chan to be her mother so another sibling rivalry ensues as to who would end up as Mu-chan's child. 

(Source: ANN)