Episode 21

The World Hair Only Grows
Kanji/Kana	髪 (かみ) のみぞ知 (し) る世 (せ) 界 (かい)
Rōmaji	Kami no Mizo Shiru Sekai
Season	2
Episode	21
Air date	March 9, 2025
Episode guide
Previous	Episode 20
Next	Episode 22

The World Hair Only Grows (髪 (かみ) のみぞ知 (し) る世 (せ) 界 (かい) , Kami no Mizo Shiru Sekai^?) is the ninth episode of the 100 Kanojo anime second season and the twenty-first episode of the 100 Kanojo anime adaptation overall.

Synopsis

Part A

An Arctic observatory predicts a new Ice Age in the near future, to Rentarou's horror. Kusuri offers a hair growth drug to experiment with hairstyles, but when Hahari takes a hair manipulation drug with it, it causes her hair to grow out of control and start molesting anyone it can find.

Part B

The girls help Rentarou escape as the hair envelops the entire world, eventually working his way back to Hahari and waking her up with a kiss. The excess hair is then sent into the sun, which is refueled to the point of averting the predicted Ice Age.

Characters

• Rentarou Aijou
• Kusuri Yakuzen
• Shizuka Yoshimoto
• Karane Inda
• Hahari Hanazono
• Iku Sutou
• Nano Eiai
• Hakari Hanazono
• Mimimi Utsukushisugi
• Kurumi Haraga
• Mei Meido
• An Baba
• Newbie Idol
• Hakari's Father

Media Covered

• Chapter 42
• Chapter 43

Parodied Scene

Scene	Parody References
Episode title	The World God Only Knows
The news broadcast about the sun dying	Akagi (original) Lord of the Rings (dub)
All the female students are entangled in hair outside the school	To Love-Ru

Manga and Anime Differences

• In the manga, Newbie Idol and her cameraman do the live commentary recording inside a helicopter. But in the anime, Newbie Idol and her cameraman do not ride a helicopter and do the live commentary recording on the top of a building.

Gallery