Uchi No Otouto Maji De Dekain Dakedo Mi Ni Konai -

A curious older sister’s desperate attempts to uncover her brother’s hidden "talent" leads to a chaotic battle of wits, locked doors, and misunderstood situations.

Despite her best efforts—sneaking into his room, setting up traps, and interrogating his friends—Ren remains one step ahead, guarding his secret with his life. As the misunderstandings pile up, Mizuki finds herself in increasingly ridiculous situations, all while trying to answer the one question that haunts her: What is Ren hiding, and why won't he show it to his own sister? uchi no otouto maji de dekain dakedo mi ni konai