Season 1 of Saito-san premiered on January 9, 2008.

Wakaba Mano and her husband Toru recently bought a house and moved to the Tokyo suburbs. Wakaba had a tough time because of her freespirited son Takeru who made her isolated from other gossiping mothers in his former kindergarten. In this new town, Wakaba is so determined to blend in with the others.

One day, Wakaba met Saito-san a 30-year-old housewife. Since her husband is always abroad for business, she is responsible for protecting her only son Junichi’s future. Junichi goes to the same kindergarten as Takeru, where other parents all seem to avoid Saito-san because she is too straightforward. For Saito-san, what is wrong is wrong. She is never afraid of confronting bad mannered people. The righteous, dignified lone mother Saito-san’s way of life gradually influences Wakaba and the other people in town.

Season 2 of Saito-san premiered on July 13, 2013.

Set five years after "Saito San," Masako Saitou now has a son in the 4th grade of elementary school. She moves to a new town and meets new people. Masako Saitou faces many problems at the elementary school and has to deal with the parents of her son's classmates and also the teachers.