The Kindergarten Detective - Season 1

Shinichiro Hanasaki, a former detective and principal of Nikoniko Nursery, faces a 60 million yen demand from new building owner Ren Yamauchi, and is also tasked by detective Jojima with rescuing Hitoshi Kamose from the Momoi Group, leading him to confront the gang leader.

Shinichiro is surprised when Hitoshi, who was supposed to return to the countryside, asks to work at the nursery. Hanasaki also takes on a job for Keiko Imai, the mistress of a yakuza boss, to pay off a debt. Meanwhile, a newborn baby is abandoned at the nursery, and a mother threatens to sue over her child's injury.

Shinichiro is tasked with finding Shigenori Motoki, a Momoi Group member, to recover money and rough him up. While searching, Shinichiro meets Yoko Ono, who knows about the recently abandoned baby at the nursery. Meanwhile, Hitoshi attempts to help by acting independently.

The outdoor air conditioning unit at the nursery is stolen, leaving the children cold. Shinichiro receives an offer from Ren to find a specific unit within two days in exchange for waiving a payment and providing a new air conditioner. However, he is distracted when a kidnapping occurs at the nursery due to Hitoshi's negligence.

Shinichiro is asked by Towa Hasegawa to care for a girl named Maria and find her mother, revealing she is Ren Yamauchi's child. Shinichiro is instructed to keep this confidential. Meanwhile, a conflict with the Momoi Group leads to Yamauchi being stabbed.

Shinichiro is asked by a child named Kotetsu to find his father. He also takes on a job to temporarily hold some data, despite warnings of a potential threat. Kotetsu's father shows up at the nursery, but Kotetsu's mother, who is raising him alone, refuses a meeting.

Shinichiro is arrested due to Takashi Yamato's grudge. The choreographer Emiko Barnaby, who is Ayane Mizukawa's grandmother, visits the nursery, but Ayane's mother Kozue cannot forgive her. Meanwhile, the rent payment deadline to Ren is approaching. What will happen to the nursery in Shinichiro's absence?

At the Nursery, Minami and Suzuna plan a group date, causing anxiety for Hitoshi. Meanwhile, Shinichiro investigates the late Kenichi Iida's infidelity for his widow, Natsuko, uncovering surprising details about Kenichi's past that even his daughter Noriko did not know.

Shinichiro learns that Risa Sasari is missing and rushes to confront Ren, only to find he’s not involved. Hanasaki frantically searches for Risa while the Department of Health and Welfare investigates abuse complaints against Minami Ohara.