There are three good reasons why dashing Civil War hero and New York lawyer William Teague cannot tell artist Mae Kendrick he’s in love with her. One, she told him he was dull. Two, she is the niece of an important client. Three, she just hired him to find the man she doesn’t remember marrying.

As Will manages this peculiar case, the search for Mae’s husband unveils a shocking discovery about her childhood, one that shifts the investigation to the place of her birth—Ireland.

But on the voyage overseas, circumstances become increasingly bizarre. Mae suffers ghost-like visions and further memory loss, and Will is seduced by a beautiful stranger who just might be trying to kill him. When Mae suddenly vanishes like her husband, Will is forced to enter a thin place, an ancient monastic ruin leading to Ireland’s Celtic otherworld, in what becomes a race against time to find her.

But are Will’s war-honed instincts any match for the alluring forces of Irish legend? Can he distinguish friend from foe? Can he protect Mae from the apparitions of her past? And how far beyond the breaking point can his secret love be tested?