Emiri Iwai

One day, a city suddenly disappears. Takuya, a professional by-the-contract courier and lone wolf, meets Yuki, the only survivor from the city's extinction. The two rely on a message from Yuki's father, who was heard to be missing, and head toward the disappeared city, Lost. However, unexpected obstacles strike before the pair, with the reality especially shocking for Yuki. Before them are the feelings of those left behind, a mysterious group manipulating in the shadows, and unveiling the hidden conspiracy. Takuya and Yuki, who both were initially strangers, would deepen their bond during the journey and unravel the mystery of the Lost city.

Aoi prefers indoor hobbies and is afraid of heights, but her childhood friend Hinata loves to show off her passion for mountain climbing. As young children they once watched the sunrise from the top of a mountain, and now they've decided to take up mountain climbing in hopes of seeing that sunrise again. They have cooking battles with mountaineering gear, climb small hills in their neighborhood, and meet new mountaineering friends as they learn the ropes of the hobby. When will they finally see that sunrise again?