On Wings of Time — Linda Boulanger

Six hundred years lay between the man with a dragon's soul and the only woman who could unlock his powers. When an impossible encounter hurls them through time, he has six days to not only prepare for the battle on the horizon, but to win her heart. Fate's carefully woven web is about to be tested by human will, a kiss, and the flip of a coin. On Wings of Time is the first book in the Lochlainn Guardians series, and although each book is a complete story about a certain couple, they are also all a part of a bigger story.