I know that it's late but because of the Spirit of Christmas (or as I call it Horny Ghost Inn) I wanted to recommend one of my favorite books that takes place at an inn during Christmas and has slight mystic tones . I should mention first off It's not written for adults though It's a lovely book. It's in that weird category where it's not exactly young adult fiction but it's definitely not small children fiction and saying junior fiction sounds oddly dismissive. The book is called Greenglass House. Here's how Goodreads describes it:
"It’s wintertime at Greenglass House. The creaky smuggler’s inn is always quiet during this season, and twelve-year-old Milo, the innkeepers’ adopted son, plans to spend his holidays relaxing. But on the first icy night of vacation, out of nowhere, the guest bell rings. Then rings again. And again. Soon Milo’s home is bursting with odd, secretive guests, each one bearing a strange story that is somehow connected to the rambling old house. As objects go missing and tempers flare, Milo and Meddy, the cook’s daughter, must decipher clues and untangle the web of deepening mysteries to discover the truth about Greenglass House—and themselves"
It's a fun little read and I recommend it if you just want a cozy story for a few hours.