Along with three others, Natsu wakes up without an idea of what has happened; the quartet reaches an island to try to figure out a way to survive.

Convinced that Botan has kidnapped them, Natsu and Arashi sneak out of camp and run into another survivor; Botan reveals what she knows.

Natsu's clumsiness indirectly leads Team Summer B to the rest of the group; her memories help them figure out their location -- and their next moves.

Arashi, Natsu and Semimaru stumble on the Team Autumn settlement in the former Kobe region; they seem to be thriving, but their leaders are tyrants.

In the ruins of Tokyo, Natsu, Arashi and Semimaru meet Team Winter's sole survivor; Team Spring reaches Mount Ogino Fuji and finds Natsu's message.

Aramaki joins Team Spring, despite Fujiko having doubts; Hana decides to search for Arashi after hearing that Aramaki met someone who fits his description.