Mystery Revival: I Picked Up a Ghostly Little Sister from the Start

As the mysterious returns and ghosts roam the night, unlucky Hailou opens his door and finds a ghostly little sister. From then on, his whole family is thrown onto a deadly path between human and ghost. How can they protect their family in a terrifying world? Why does his ghostly little sister keep finding new "family members"? Trapped in one ghostly prison after another as they suddenly appear, Hailou struggles to find the answers...