A quartet of comedic rock stars called "Mountain Horse" unexpectedly gain superhuman powers after listening to a rock concert they opened for. The powers themselves are not very strong, but enough that they get noticed by Fuurouta of the Superhuman Bureau, and a publicity agent named Fugimoto. After overhearing Fugimoto's plan to sell chocolate with an experimental anti-superhuman chemical inside, the group decides to infiltrate the warehouse and destroy the chocolate before its distribution, though they have to fight against a giant security robot and a rival superhuman rock band. After one of them gets killed in the fight, the band successfully destroys the chocolate, and keeps one sample as insurance against Fugimoto. Despite Fuurouta and Jiro's offer the remaining band members decide not to join the Superhuman Bureau, and instead continue going on stage as a comedy group.