“That Woman in the Croft” is a mystery-thriller set in the atmospheric Highlands of Scotland. It centers around the decaying MacCallum Lodge, a once-prestigious hunting lodge struggling financially. Tensions run high among the staff and guests, particularly between the lodge owner, Hugh MacCallum, his younger wife, Isla, and the rugged gamekeeper, Robbie McTaggart. As whispers of infidelity and unspoken desires simmer beneath the surface, the arrival of the mysterious and alluring Siofra Ravensway turns the lodge's dynamics on its head.

Siofra, with her striking beauty and mysterious presence, captivates the men of the lodge, including Robbie, much to the dismay of Isla and the quiet jealousy of Morag, the housekeeper. Meanwhile, local gossip, led by the superstitious Agnes Maclean, fuels suspicions about Siofra, linking her to old Highland legends of the Baobhan Sith, a vampiric figure known to lure men to their doom.

One fateful evening, after a tense night at the lodge bar filled with flirtations, jealousy, and unresolved emotions, Robbie disappears into the mist with Siofra not far behind. The following day, his body is found at the edge of the forest, sparking a murder investigation that uncovers the dark secrets lurking within the lodge's walls and the village's superstitions. As the mystery unfolds, the truth becomes entangled with myth, and the line between reality and legend blurs.