Recorder to Randoseru

Synopsis:

The Miyagawa siblings are much like any other brother and sister, except for one major difference: high-schooler Atsumi could pass for an elementary school student, yet her much younger brother, Atsushi, has the appearance of an adult! Although short and cute Atsumi can't even go shopping alone due to her inability to reach the top shelf, she remains a hit with the boys in her class, while Atsushi’s height and naïve schoolboy demeanor frequently make him seem more like a child molester than a young and spritely fifth-grader – much to his teacher's frequent dismay and horror. With Atsushi constantly being mistaken for an adult, the poor boy can't even offer the girl he likes a scarf to keep her warm without being arrested. Is it possible for these two mismatched siblings to live a peaceful life, or will they always be tormented by their abnormal heights?