This is the second book in a series, and really should be read in order. 
 Thad and Sara are getting used to being a couple, planning a quiet, somewhat cheerful Christmas at Thad's home in the bayou. Though a nominal Hindu, Sara's parents celebrated a secular "American" Christmas, and he's a little homesick missing his family. Thing is, weird lights are appearing in the mist, and leading people out into the murk. It even grabs hold of Thad, who (as a vampire) is totally light-sensitive, but it doesn't affect Sara for unknown reasons. As such, Sara is a super important part of the investigation, which irks Thad--he wants Sara to stay home, be safe. 
 So this novella packs a lot of emotional punch. We see how Thad's emotionally dependent on Sara, and that's really endearing. They're also working on their intimacy, which Sara loves and Thad's trying not to treat as if it's sinful. Hard for him what with being raised that way. 
 ...I half carried him upstairs to our bed. 
 Our bed. 
 The bed I would share with him as long as he'd have me. Though at times my inner conflict still raged, Sara was a sin I couldn't help but commit. 
 #Swoon, really. Because what's more romantic than completely setting aside your biased, yet ingrained, religious beliefs to embrace love. 
 This mystery unfolds slowly, but has a big wallop of conflict. The "natives" aren't happy about outsiders in the bayou, and are quick to blame the witch lights--visions of light that naturally appear and are dismissed as "swamp gas" but are instead serving as a beacon--on Thad, as he's such a recluse that many feel he could be a malevolent force. Some of the townsfolk try to intimidate him into leaving. Then, a young girl goes missing and it's pretty much torches and pitchforks time. 
 All of this is happening alongside the Christmas season, and the festive spirit that Sara's trying to cultivate is dimmed by the mounting mystery. The climax is intense, with Thad and Sara combing the bayou for the missing girl, and the source of magic behind the light-beacons. I really enjoyed this, and loved that Thad embraced his human roots more. The affection growing between Thad and Sara is delightful, and I just can't wait to read more of their adventures.