Kako (Fumi Nikaido) is a female high school student. She lives at a restaurant run by her family in Kitashinagawa, Tokyo. Unexpectedly, Kako's aunt, Mikiko (Kyoko Koizumi), suddenly appears. Kako thought her aunt died 18 years ago. Her whole family is embarrassed by Mikiko's appearance due to a past incident caused by Mikiko. Kako is also irritated when Mikiko lives in her room. They spend the summer together.
Unfortunately the movie Kako: My Sullen Past is not yet available on Paramount Plus.
| Directing | Shiro Maeda | Director |
| Writing | Shiro Maeda | Writer |
| Production | Toshikazu Nishigaya | Producer |
| Camera | Yasuyuki Sasaki | Director of Photography |
| Production | Kazuhiro Ohta | Executive Producer |
| Art | Naozumi Tanaka | Art Direction |
| Production | Yoshihisa Yamashita | Associate Producer |
| Production | Hirofumi Shigemura | Executive Producer |
| Editing | Takashi Sato | Editor |
| Art | Norifumi Ataka | Art Direction |
| Production | Yuki Nishimiya | Associate Producer |
| Production | Atsushi Moriyama | Producer |
| Production | Tamotsu Kanamori | Line Producer |
| Sound | Toru Okada | Original Music Composer |
