Touring after the apocalypse 5.

Youko and Airi are riding through Gunma Prefecture when Youko collapses from inhaling Mount Asama’s volcanic gases! Luckily, a mysterious lone boy appears just in time to rescue the pair. He takes them to the nearby Kusatsu hot spring resort for some much-needed rest and recuperation―but as the girls’ relationship with him grows, getting back on the road becomes ever more complicated…