The Great Detective Kiyoshiro Yumemizu

A detective previously a professor of a college, has moved to the house next to Ai Iwasaki's. He's a reader who likes to read to the extent that he forgot to eat for three days, forgetting his birthdatesand even forgetting the cases he has solved. He saw that there are three sisters (Ai, Mai, and Mii) in Iwasaki's house!