Concept Art

Children's Book

The tears of farewell mark the beginning of a miracle journey.
With the wish to see his mama again, Mamesuke takes his first step into the adventure of the Rainbow Bridge.

Character Design

A closer look at the characters who bring this world to life

Petra

Petra is a gentle and curious young squirrel whose warm heart and earnest nature guide her through each discovery, inviting readers to see the world with childlike wonder.

Koto & Ito

Koto and Ito are lively twin squirrels who support Petra with their playful energy—always eager to help, explore, and brighten every moment they share

Stationmaster

The Stationmaster is a calm, kind hippo who watches over Petra and the town with the warmth of a gentle guardian, offering quiet support whenever it’s needed

Steam Locomotive Train

A guide who carries Petra forward. A presence like a spirit.

Environment Design

Step into the landscapes that shape the heart of this story

Sakura Town

The season is spring. Her hometown is a city of cherry blossoms that brings Japan to mind. The color is a soft, pale pink.

A cherry-blossom town, calm and beautiful, where kindness, harmony, and quiet days are shared by all. Petra sets off from his hometown to find happiness, her heart stirred as cherry blossoms fall around him.