Ninin ga Shinobuden
One day, when a high school student, Kaede, was studying for the examination, a female ninja appeared in her room. She was Shinobu, who was studying at a ninja school to become a full fledged ninja. She came here to steal Kaede's underwear because it was her assignment...
This anime is a slapstick comedy performed by Kaede, Shinobu, and a mysterious creature, Onsokumaru, who is also the master of the school.
an extended description!