A shy 11-year-old's life takes a strange turn when she discovers three hungry goblins living in the attic of her new house. She misses her old life. She misses her father so very much. Until she makes some new ghoulish friends.
Unfortunately the movie A Letter to Momo is not yet available on HBO Max.
| Directing | Hiroyuki Okiura | Director |
| Writing | Hiroyuki Okiura | Screenplay |
| Production | Keiko Matsushita | Producer |
| Production | Motoki Mukaichi | Producer |
| Production | Mariko Noguchi | Producer |
| Production | Arimasa Okada | Producer |
| Production | Kazuya Hamana | Executive Producer |
| Production | Hiroyuki Ikeda | Executive Producer |
| Production | Mitsuhisa Ishikawa | Executive Producer |
| Production | Shigeru Watanabe | Executive Producer |
| Sound | Mina Kubota | Original Music Composer |
| Editing | Junichi Uematsu | Editor |
| Art | Hiroshi Ohno | Art Direction |
| Sound | Shiro Sasaki | Music Producer |
| Sound | Yuko Hara | Theme Song Performance |
| Visual Effects | Masashi Ando | Animation Director |
| Visual Effects | Shinya Inoue | Key Animation |
| Art | Hiroyuki Okiura | Storyboard Artist |
| Camera | Koji Tanaka | Director of Photography |
| Writing | Hiroyuki Okiura | Original Story |
| Production | Keisuke Watanabe | Producer |
| Visual Effects | Masashi Ando | Character Designer |
| Visual Effects | Masashi Ando | Key Animation |
| Visual Effects | Hiroyuki Aoyama | Key Animation |
| Visual Effects | Kouichi Arai | Key Animation |
| Visual Effects | Takahiro Chiba | Key Animation |
| Visual Effects | Hideki Hamasu | Key Animation |
| Visual Effects | Ayako Hata | Key Animation |
| Visual Effects | Takeshi Honda | Key Animation |
| Visual Effects | Akira Honma | Key Animation |
| Visual Effects | Arifumi Imai | Key Animation |
| Visual Effects | Ei Inoue | Key Animation |
| Visual Effects | Toshiyuki Inoue | Key Animation |
| Visual Effects | Mariko Ishikawa | Key Animation |
| Visual Effects | Hideki Ito | Key Animation |
| Visual Effects | Takahisa Katagiri | Key Animation |
| Visual Effects | Hiroshi Kawaguchi | Key Animation |
| Visual Effects | Yuki Kawashima | Key Animation |
| Visual Effects | Takahiro Kimura | Key Animation |
| Visual Effects | Kazuchika Kise | Key Animation |
| Visual Effects | Toshiyuki Komaru | Key Animation |
| Visual Effects | Takahiro Komori | Key Animation |
| Visual Effects | Chikashi Kubota | Key Animation |
| Visual Effects | Ayumi Kurashima | Key Animation |
| Visual Effects | Susumu Mitsunaka | Key Animation |
| Visual Effects | Hiroyuki Morita | Key Animation |
| Visual Effects | Takashi Mukouda | Key Animation |
| Visual Effects | Tatsuzo Nishita | Key Animation |
| Visual Effects | Tetsuya Nishio | Key Animation |
| Visual Effects | Kazuya Nomura | Key Animation |
| Visual Effects | Hiroyuki Okiura | Character Designer |
| Visual Effects | Masashi Okumura | Key Animation |
| Visual Effects | Kiyotaka Oshiyama | Key Animation |
| Visual Effects | Takuya Saito | Key Animation |
| Visual Effects | Izumi Seguchi | Key Animation |
| Visual Effects | Hiroshi Shimizu | Key Animation |
| Visual Effects | Tomohiro Shinoda | Key Animation |
| Visual Effects | Ayumi Shiraishi | Key Animation |
| Visual Effects | Shinji Suetomi | Key Animation |
| Visual Effects | Akira Takata | Key Animation |
| Visual Effects | Hideki Takahashi | Key Animation |
| Visual Effects | Atsushi Takeuchi | Key Animation |
| Visual Effects | Teiichi Takiguchi | Key Animation |
| Visual Effects | Takahiro Tanaka | Key Animation |
| Visual Effects | Yuuga Tokuno | Key Animation |
| Visual Effects | Katsuya Yamada | Key Animation |
| Visual Effects | Makoto Yamada | Key Animation |
| Visual Effects | Akiko Yamaguchi | Key Animation |
| Visual Effects | Fumiko Yoshida | Key Animation |
| Visual Effects | Yoh Yoshinari | Key Animation |
| Visual Effects | Shinya Ohira | Key Animation |
| Art | Kazuo Oga | Background Designer |
| Visual Effects | Tooru Ookubo | Key Animation |
