Nathaniel by Carole Mortimer

Taking a much-needed holiday in North Wales, journalist Chloe Evans discovers a castle not listed on any of the dozen or so maps she has of the area. The nearest thing she can find is the remains of a castle that used to be there but crumbled into ruin many centuries before. Her curiosity getting the better of her, Chloe decides to find out more about this imposing grey stone castle and anyone who might live there.
The locals, she discovers, call it Pendragon Castle. When Chloe asks them more probing questions some say there are half a dozen male members of the original family still in residence, and that they’re brothers. Others claim there to be more, or less, than that number. But all, without fail, describe those men as being big and muscular, more handsome than any man has a right to be, with eyes capable of mesmerizing and seducing any woman who falls under their spell. Some of those people add a knowing wink, others a warning not to venture too near the castle, and to certainly keep her distance from the men living there.
Visitors staying at the same small hotel as Chloe talk of seeing bright lights and helicopters landing on the mountain late at night, and of hearing strange noises that sound like the roars of wild animals.
There was a story here, Chloe was certain of it.
Whatever the mystery is regarding Pendragon Castle and the men who live there, Chloe decides she isn’t leaving Wales until she’s discovered exactly what’s going on.
While exploring the area around the castle, Chloe is challenged by the dark and taciturn Nathaniel. A man who fits the description of the castle’s inhabitants exactly: well over six feet tall, handsome as sin, with shoulders wide enough to fill a doorway, and eyes the colour of the clearest emerald.
The moment she gazes into those mesmerizing green eyes Chloe realises she should have run while she still could.