Despite the otherworldly situations he’s gotten into, Keiichi’s everyday joy is still found as an engineer and mechanic. And as Chihiro’s training retreat by the seashore continues, the two of them put that shared passion into practice by building two bikes based on different philosophies, with the help of her old high-school friends, Eri and Tasuga — plus (or maybe minus) the help of Urd and Skuld!