He is then told that a fragment of the comet Tiamat fell to earth three years ago and obliterated Itomori and its surroundings, killing a third of the town's population.

While they continue with their plans, Taki realizes that Mitsuha might be in his body at the shrine and heads back to the mountain to meet with her.

As time begins to pass, their memories of each other start to fade and disappear; both of them forget each other's names, as well as the events that happened between them.

Mitsuha confronts her father again with a new spirit of determination, and soon after, the broken fragment of Comet Tiamat crashes to Earth, destroying Itomori.

Eight years later, it is revealed that Mitsuha persuaded her father to conduct an emergency evacuation drill across the surrounding districts, allowing most of Itomori's residents to escape in time and survive.

He finds himself attracted to items relating to Itomori, such as magazines and people he thinks are familiar (whom he actually knew when he was in Mitsuha's body).

They get out at their next stops and try to find each other; they finally meet at a staircase and, feeling as though they know each other somehow, ask for each other's name.... By September 2016, the light novel had sold around 1,029,000 copies.

The light novel was written by Makoto Shinkai and Arata Kanoh, with illustrations by Masayoshi Tanaka and Hiyori Asakawa.

Another Side: Earthbound also received a manga adaption, written by Arata Kanou and illustrated by Junya Nakamura, through the Cycomics app in July 2017.