Anon is riding on a bike trail when a Marisa jumps out, demanding a toll. Not wanting to get his bike dirty, he stops. That's when the rest of the family comes out, a Reimu with one koyukkuri of each type. They demand sweets, but he tells them he doesn't have any, and offers them a ride on his mountain bike... which is his way of justice.
Initially, they enjoy the gentle speed, and are impressed by the green field they come to. That's when Anon picks up speed, just as Marisa gets a bad feeling. He tells them to hold on tight, as he won't care about anyone who falls off. As they go faster and faster, only Komarisa is enjoying the speed; the other yukkuris find it scary.
That's when he starts going downhill. A bump sends Koreimu flying out of the basket, and she lands in front of the bike and gets crushed. Before the parents can worry about it, he hits a rough trail, and the bumpiness gets them turned on, and they start refreshing.
He hits another bump, and because they forgot to hold on tight, they fly out and splatter across a tree. Komarisa is pleased by the ride, and has forgotten about its family. Anon invites it to his home, and as it accepts, he wonders how he'll play with it.