Bowen Penhallow has always been a loner, studying dark and ancient magic. But when his friend Colin asks him to attend a Yuletide wedding at a grand estate deep in the Welsh countryside, Bowen reluctantly agrees. Tamsyn Bligh is not a witch, but she makes her living off of them. As a procurer and seller of magical items, Tamsyn’s business is not always above board. Bowen is an occasional customer—as well as the star of several of Tamsyn’s dirtiest dreams—but she’s been around enough witches to know that, as a human, getting involved with one is not the smartest idea. She’s finagled an invite to the Witchy Wedding of the Century in the hopes of finally making a score big enough to retire. But Tamsyn isn’t the only one sneaking about in Tywyll House, and the mix of a very strong spell combined with a wedding mishap transports Bowen and Tamsyn into Tywyll House’s past, to the Yuletide Celebration of 1958.