Onegai Teacher!

Please Teacher! (おねがい☆ティーチャー Onegai Tīchā?, Onegai ☆ Teacher), is a Japanese anime series, directed by Yasunori Ide and written by Yōsuke Kuroda, and produced by Bandai Visual, which was adapted into a manga and light novel, centering around a group of friends and the odd things that happen to them after they get a new teacher.

The Please Teacher! anime series premiered in Japan on the WOWOW satellite television network between January 10 and March 28, 2002, spanning a total of 13 episodes, including twelve originally premiering on television plus an OVA episode released on DVD on October 25, 2002. It was adapted very soon into a manga, serialized in MediaWorks's shōnen manga magazine, Dengeki Daioh, in January 2002, and was also later adapted into a light novel, entitled Onegai Teacher: Mizuho and Kei's Milky Diary, published in March 2003.

The Please Teacher! anime series was soon continued with a spin-off sequel, Please Twins!, which premiered on WOWOW between July 15 and October 14, 2003.

The setting of the series, though left unsaid in either anime or manga, is Lake Kizaki, located in Nagano, Japan, and the region and its surrounding locations are featured prominently and accurately across the series. The novel states that the school the characters attend is the Nagano Prefectural Kizaki High School. This school is based upon the Old Matsumoto High School located in Agatanomori Park of Matsumoto, about an hour south of Lake Kizaki on the JR Ōito Line. The tower of which Kaede and Hyosuke stand upon can be found in Joyama Park on the northwest part of the city. It takes place some time in the future after 2009.

Plot
Kusanagi Kei, a high-school student living with his aunt and uncle, has an encounter with a female alien. This alien is revealed to be a new teacher at his school. Later, he is forced to marry this alien to preserve her secrets. From there, various romantically-inclined problems crop up repeatedly.

Also has a sequel called Onegai Twins. In total both series have 26 episodes. 12 TV and bonus OVA.