A strict but loving grandma solves a myriad of issues for the people around her! Doumeki Miki lives in a small rural village surrounded by abundant nature and beautiful scenery. After becoming a widow at an early age, she’s spent many years working as a leader in her village. A beautiful, intelligent woman in her 70s, she’s incredibly spry, with perfect posture.
A popular English teacher, Mizuguchi Risako has been kidnapped three days before the high school's graduation ceremony. Four high school seniors received a mysterious challenge letter, asking them to solve the mystery of the kidnapping case within 72 hours. The four students are Kurokawa Yoshiki, his childhood friend Takahata Ayane, sports all-rounder Ogita Junpei, and school's beauty contest winner Komatsu Mio. The four students were wondering why they're the only ones who received the letter, but later gradually found out the "other face" of Mizuguchi which she has been hiding.
Shohei Kazama (Kinya Kitaoji), who travels all over the country and works as a special police chief, is new to the Iwaki Tokiwa Police Station in Fukushima Prefecture. Kenichi Nishino (Yuma Nakayama) and Kanji Takizaki (Hiroki Okada), the head of the criminal division, express their repulsion. Dai Kuramochi (Hiroshi Katsuno), an alumnus of the Fukushima Prefectural Police, tries to calm him down, but for some reason he continues to show hostility. At that time, Hisashi Ono's (Ichiro Ogura) body is found.
Rika Adachi (足立梨花) is a Japanese tarento and actress. She was born in Nagasaki Prefecture, and raised in Mie Prefecture. She has appeared in several films, including Say "I love you" and Ghost Theater, and has played leading roles in the TV Drama Kinkyori Renai: Season Zero and Yōkoso, Wagaya e.