Protecting my Human by Eve Langlais

I just wanted to be left alone, but then SHE came along.

Alistair’s been around for eons because his gift allows him to live undetected among the humans. However, his peaceful existence on Rum Island is shaken up with the arrival of a history professor in search of treasure.
Davina isn’t some dry and dusty scholar but a vibrant woman in her thirties who’s taken a sabbatical to write a book about Scotland’s lost treasures. Her research takes her to Kinloch Castle, where the grumpy Alistair sends her packing, but when he spies her falling off a cliff, he literally swoops to her rescue, revealing his scaly side.
As you can imagine, Davina is very curious about the man who can shapeshift into a legendary beast—much to Alistair’s annoyance. Getting rid of her is proving troublesome, though, and not just because she intrigues him. According to a selkie, their fates are tied.

The reluctant Alistair finds himself joining Davina on a trip to Loch Ness and, along the way, discovering that love is the most valuable thing a dragon can hoard.