Yuma-chin makes a surprise appearance on a boys' school trip as a bus guide! Her natural spirit of service runs wild as the students become enthusiastic, and her teenage dick instantly gets hard! She gives a blow job to a car-sick student, has a lucky encounter with a student returning while she's masturbating in an unmanned parked car, seduces the class representative who comes in while she's drinking at an inn and seduces him while the teacher is out, and then storms into a room in a yukata to take a commemorative photo, leading to a striptease and orgy.