At school, Aoyama finds Uchida and his other classmate Hamamoto with a penguin named Penta on the rooftop.

Aoyama then goes to a cafe to play chess with the Lady, where she mentions her trouble sleeping after reading about the Jabberwock.

Aoyama later deduces that the Lady can turn thrown objects into penguins in the light and bats in the dark.

The next day, Hamamoto leads Aoyama and Uchida deep into the forest, where a floating sphere of water sits, which she calls the "sea".

Entering despite the warnings, they find Hamamoto's father conducting research, with Suzuki revealing the sphere's location.

The next day, it is revealed that the sphere has expanded to a dangerous extent, leading to the disappearance of Hamamoto's father.

Aoyama and the Lady return to the cafe to talk, while the mob of penguins slowly disappear.

Penguin Highway is a novel written by Tomihiko Morimi, which was originally published by Kadokawa Bunko in tankōbon format on May 28, 2010.

[7] Yen Press announced at Anime Expo 2018 that they would be publishing the novel in English,[8] with a hardcover release on April 23, 2019.

[10] A manga adaptation of the novel was serialized from March 27, 2018, to February 27, 2019, in Media Factory's Monthly Comic Alive magazine, with illustrations by Keito Yano.

[2] Hiroyasu Ishida serves as the director for the film, with Yōjirō Arai responsible for character design, Makoto Ueda writing the screenplay, and Umitarō Abe composing the music.

[19] Eleven Arts announced that they would be distributing the film theatrically in North America, where it premiered at Crunchyroll Expo in San Jose on September 2, 2018,[21] and a wider release on April 12, 2019.

[26] Penguin Highway received the Excellence Award in the animation category at the 22nd Japan Media Arts Festival.

[30] On Metacritic, the film has a weighted average score of 82 out of 100 based on 4 critics, indicating "universal acclaim".