The Other Side of Secret

Seven years ago, Yuuto's older sister vanished through a mysterious door, leaving him with only a necklace as a keepsake. Now, he has once again glimpsed that same enigmatic door—and this time, he watches two mysterious girls (Saya and Hina) disappear through it. Driven by hope of finding answers about his sister's fate, Yuuto and his pet cat follow them into the unknown. Beyond the threshold lies a strange and dangerous world, one that holds secrets connected to his sister's disappearance. As Yuuto navigates this perilous realm, he must confront challenges that will test his resolve and force him to grow in unexpected ways. Saya, one of the girls he followed, becomes his guide in this unfamiliar land, suggesting that the answers he seeks may require more than just courage—they may demand a deeper understanding of the world he's entered and the choices he makes within it. (Source: MangaHelpers)