•
Maika Yamamoto as Chiyomi Horikiri: Member of the dance club and writing her own fantasy stories, which she posts online in installments. Former childhood friend and sweetheart of Shunichi. She shrinks to 15 cm after wishing to go back to her childhood days and a fight she had with her parents •
Taishi Nakagawa as Shunichi Minami: Former childhood friend and sweetheart of Chiyomi who formerly practiced
kendo and whose father left them when he was younger. He is preparing himself for medical school – he hopes to become a doctor •
Erina Nakayama as Sayuri Nomura: A classmate of both Shunichi and Chiyomi. She relates to Shunichi due to a similar situation she is in with her mother disappearing. Most of the male students swoon over Sayuri, giving her the nickname "Pheromones" because they find her so sexy, but she does not seem to have any friends. She is head over heals for Shunichi and often pursues him. When she openly admits her feelings for him, he eventually turns her down and in the end, finally admits his feelings for Chiyomi. •
Mirai Suzuki as Riku Tagaki: Another classmate who is friends with Chiyomi and Ami. Riku has feelings for Chiyomi and doesn't like Shunichi for the way he treats her. He suspects that Minami had something to do with Chiyomi's disappearance. In episode 9, Riku learns the truth and confronts Shunichi about it. This leads to him learning about Chiyomi's shrunken form and her true reason for disappearing (she is actually in hiding). •
Riko Yoshida as Asuka Horikiri: Chiyomi's sister, who is kind to her. She is friends with Shunichi Minami and is the only one aside from Sayuri he hasn't acted cold around. In Episode 8: she is the first to learn about Chiyomi's shrunken form apart from Shunichi and tries to keep the secret. •
Naomi Akimoto as Noriko Horikiri: Chiyomi's strict mother who is a realist, but is also secretly a romantic. She finds Chiyomi in her shrunken form in Episode 10 after Shunichi is in an accident. •
Narimi Arimori as Emiko Minami: Shunichi's mother who is worried about her son. Her husband left her, which put her in a bind, having to raise her son alone, but she no longer holds it against him. She later discovers his relationship with Kana and accepts his petition for divorce. •
Moe Sasaki as Ami Mikimoto: Chiyomi's best friend, who is in the same dance club. She may have a crush on Riku, but keeps it top secret. •
Ichirota Miyagawa as Noburo Minami: Shunichi's father who mysteriously disappears during junior high. He taught Shunichi
kendo. It is eventually revealed in episode 5 that Noburo is in a relationship with Sayuri's mother, Kana. •
Kouichi Oohori as Jouji Horikiri: Chiyomi's father who works as a florist. He is also strict with Chiyomi when it comes to her future. In Episode 10, he learns about Chiyomi being tiny and faints upon seeing her in Noriko's purse •
Kazue Tsunogae as Tomiko Minami: Shunichi's grandmother, who tells him and Chiyomi the legends of
Issun-boshi and the one-inch princess known as Issun-hime. Tomiko learns about Chiyomi's shrinking in episode 6, though at first she believes she is the one-inch princess of the legend. ==2024 cast==