All Hallows in the Gallowglass - Robert C. Young

When the trail cameras start capturing footage that shouldn't exist, an owl with the wrong eyes, a deer with the wrong bones, Artie brushes it off as a trick of the infrared. He won't get the chance to brush off what happens next. Something old walks the Expanse on Samhain night, curious and patient and utterly unlike anything in his training manual. And when a local teenager goes missing on a dare, Artie and his unlikely colleague Gordo will have no choice but to face it head-on, with nothing but a torch, an old piece of forest folklore, and a small, fearless dog who's known all along that something was wrong.

A longer, spookier standalone adventure set years before the events of Series 1, All Hallows in the Gallowglass is the perfect entry point for new readers, and a treat for longtime fans who'll spot the quiet echoes of everything still to come.

For readers of The X-Files and Midnight Mass. No prior reading required.