Remember those cartoon character-based undergarments that kids used to wear? How many of those brightly colored sets were sold in the hope that they might actually grant someone superpowers? And what if they actually could? Three young Japanese Oni are about to answer that question when they're transferred into a normal middle school as part of a plan to ease relations between humans and demons! How? Because when extra-large problems arise, they can don special tiger-striped underpants... Oni-Pants... that let them transform and use special Oni abilities to make brief work of the issue! Of course, with great underwear comes great responsibilities (and the danger of accidental Mooning while in senshi mode), but if someone has to wear the big girl undies, then the future's foundation will hopefully be fundamentally secure with ONIPAN!