The Haunted Bookstore - Gateway to a Parallel Universe (Manga)

Kaori lives in a bookstore where the boundaries between the mortal realm and the spirit realm are blurred. She spends her days in peace, selling books to otherworldly beings alongside her adoptive father, a spirit himself. But all of that is disrupted when a self-proclaimed exorcist stumbles into this ghostly utopia. Can Kaori embrace her better nature and help a man who's vowed revenge against all spirits find his way back home?