Mason Mooney is totally Grimbrook's best paranormal investigator, OK? Sure, Grimbrook is home to the Paranormal Society, a group of cool teens who explore ghostly happenings around the globe, but all Mason needs is one case to prove he's the real deal. His chance comes in the form of Iris, a chatty, inquisitive girl who recently moved to Tanglewood Mansion and thinks specters are haunting her "meanie butt sister." She and Mason decide to investigate, and aloof, snobby Mason starts to warm towards his new acquaintance as they scout portrait galleries, attics, and even a séance. Mason Mooney is a great fit for middle-schoolers who appreciate over-the-top characters and cheeky, fourth-wall-breaking narrators that let them feel they're in on the joke. Miller's artwork utilizes loose, squiggly lines and a colored-pencil-like texture, which adds to the fun. One full-page spread shows Mason and Iris exploring Tanglewood via a dollhouse view; in it, Iris peppers Mason with questions as Mason grows increasingly irritated. The optimistic ending suggests Mason and Iris will have even more eerie adventures in the future.