100 Days Until We Break Up: Story, Cast and Series Facts

Story and premise

Kasuga Yuma and Hasegawa Itsuki gained public attention after an interview about the partnership oath system for sexual minorities went viral on social media, with many users describing their dynamic as "moe." When they are offered the chance to film a documentary chronicling 100 days of their life together, Yuma eagerly accepts in hopes of helping "spread understanding of homosexuality." Despite having already broken up, Yuma convinces Itsuki to continue acting as a loving couple in front of the cameras. Unaware of the truth, director Kayano Shiho is determined to capture their relationship as authentically as possible.

Series details

• Title: 100 Days Until We Break Up
• Format: Scripted
• Language: Japanese
• Genres: Drama, Romance
• Premiere date: 2026-05-26
• Final broadcast date listed: 2026-06-30
• Status in TVmaze: Ended
• Network listed by TVmaze: MBS
• Network country: Japan
• Typical episode runtime: 30 minutes
• TVMaze ID: 91382
• IMDb ID: tt41764389
• TVDB ID: 476741

Cast and credited roles

• Kentaro Ito — Yuma Kasuga
• Kanichiro Sato — Itsuki Hasegawa
• Yui Narumi — Shiho Kayano
• Kenta Yamada — Yamada Kentaro
• Masumi Nomura — Mori Naomi
• Kaoru Mitsumune — Katagiri Asuna
• Asuka Kudo — Kubota Shinya
• Naoto Takenaka — Hinode Isao

Seasons in the TVmaze catalogue

• Season 1: premiered 2026-05-26; final listed air date 2026-06-30; episode order: 6.

Source and licence

Adapted from 100 Days Until We Break Up on TVmaze. The synopsis is reproduced as plain text; catalogue facts, cast and season records are selected and reformatted. This adapted text is available under CC BY-SA 4.0, following the TVmaze API licence. Network and web-channel credits identify the service listed in this source; they do not establish current streaming availability.