Highlander Hunted by Rebecca Preston

When Helena awakes in the Scottish moors near MacClaran Keep, centuries in the past, she finds a whole new way of life and becomes drawn into a mystery plaguing the local village.
Geologist and spelunker Helena’s interest in the rumored hidden cave system under the MacClaran Keep ruins leaves her stranded. When she awakes and finds herself, not in the cave, but out on the moors near the castle—which is whole and looks fairly new—she’s disoriented and terrified which sends her running headlong into Brendan MacClaran.

Brendan spends his days caring for and teaching the old Laird’s son, mourning the death of his beloved Brigid, who died six years earlier. When children start disappearing from the local village, he suspects the culprit isn’t fairie monster of Celtic legend—the Blank Annis—but rather his insane future mother in law, Anne.

When Helena—the reincarnation of Brigid—appears in the moors, Brendan can’t deny that the family curse has brought her back to him. Together, they must face their growing attraction and use Helena’s expertise to solve the mystery and find the missing children.