Series synopsis
A Summer's Accomplice, also known as ひと夏の共犯者 is a Japanese mystery television series that premiered on TV Tokyo on October 4, 2025. It ended on December 20, 2025. It stars Masaki Hashimoto, Yuri Tsunematsu, Riko Nagase and Ruka Ishikawa.
A devoted university student's idol obsession takes a dark turn when he shelters his wounded celebrity crush after her scandalous romance makes headlines, only to uncover her hidden split personality and suspected involvement in a musician's murder—forcing him to choose between love and truth in a dangerous descent into twisted loyalty.
Premise
A devoted university student's idol obsession takes a dark turn when he shelters his wounded celebrity crush after her scandalous romance makes headlines, only to uncover her hidden split personality and suspected involvement in a musician's murder—forcing him to choose between love and truth in a dangerous descent into twisted loyalty.
Cast and characters
Leading cast
- Masaki Hashimoto as Takumi Iwai
- Yuri Tsunematsu as Mio Katagiri / MIO / Maki
- Riko Nagase as Aina Amase
- Ruka Ishikawa as Mona Chikusa
- Jyotaro as Shota Mizukawa
- Amane Uehara as Ema
Episodes
This series spans 2 seasons with 13 episodes.
| Season | Episodes | First aired | Last aired |
|---|---|---|---|
| Season 0 | 1 | December 27, 2025 | December 27, 2025 |
| Season 1 | 12 | October 4, 2025 | December 20, 2025 |
| Episode | Title | Air date |
|---|---|---|
| 1 | Special | December 27, 2025 |
| Episode | Title | Air date |
|---|---|---|
| 1 |
Episode 1 Living together with your favorite idol is like a dream... But she might be a murderer!? A suspenseful love story begins, featuring a man falling into a phantom love and a dangerous, heartbreaking escape! |
October 4, 2025 |
| 2 |
Episode 2 "My beloved idol might be the murderer..." What's more, she has another personality inside her... A suspenseful love story about a man who becomes an accomplice and falls into depravity! |
October 11, 2025 |
| 3 |
Episode 3 Takumi (Hashimoto Masaki) and Mio (Tsunematsu Yuri) are shocked by the arrival of Mona (Ishikawa Ruka), Takumi's childhood friend. They enjoy a fun time at the festival, but at the same time, Mio's disappearance causes a stir in the world...!? |
October 18, 2025 |
Production
Release
| Original network/platform | TV Tokyo |
|---|---|
| First aired | October 4, 2025 |
| Last aired | December 20, 2025 |
| Runtime | 23 minutes |
| Status | ended |