Uchi No Otouto Maji De Dekain — Dakedo Mi Ni Kona...

Originally starting as a web-based project, the series follows the daily life of an older sister and her younger brother. The "hook" of the story is established immediately in the title: the younger brother has undergone a massive growth spurt—both in physical stature and "other" attributes—leaving the sister in a state of constant shock and curiosity.