His Firefly Cowgirl (Devils on Horseback: Millennium #1)

Dax Blackwood had more than his share of troubles and then she returns to Tanger, Texas, to set his world on its ear. Sophie Evans didn’t plan to ever return to the town she grew up in, but when a suspicious fire destroys a town landmark, she’s assigned to investigate as a state fire marshal. Sparks threaten to flare out of control when this cowboy meets his firefly cowgirl once again.