(W/A) Sakae Saito. 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...