Umaru Doma is a model student with a secret: when she comes home from school, she slips on her hamster hoodie and transforms into a slow otaku who enjoys junk food. As Umaru's everyday shenanigans continue, her relationship with her classmates—Nana Ebina, Kirie Motoba, and Sylphinford Tachibana—deepens, and more and more exciting occurrences emerge. Of course, these occurrences raise a slew of issues. What question did Nana pose to Umaru's brother Taihei? What is the identity of the strange girl with the diamond hairpin? Most importantly, why does this girl appear to know Umaru? These and other questions will be addressed in Himouto! R, Umaru-chan!