Chaz is now living with Waluigi, Shadow, and Faye Valentine, and due to their (and my) severe hatred for Kpop Demon Hunters (like a normal person should), they have awoken the most obnoxious, screamingest, deadliest entity ever: Rumi. The four can't defeat her alone, so they must unite with other toons to save the world a whopping fourth time! This is it... Will Earth cease to exist?
Also, this movie's main lesson is to never be a KPDH fan, EVER.