A Killing Cold by Kate Alice Marshall

A woman invited to her wealthy fiance’s family retreat realizes they are hiding a terrible secret—and that she’s been there before, by the bestselling author of What Lies in the Woods.

A whirlwind romance.
When Theodora Scott met Connor—wealthy, charming, and a member of the powerful Dalton family—she fell in love in an instant. Six months later, he’s brought her to Idlewood, his family’s isolated winter retreat, to win over his skeptical relatives.

Stay away from Connor Dalton.
Theo has tried to ignore the threatening messages on her phone, but she can’t ignore the footprints in the snow outside the cabin window or the strange sense of familiarity she has about this place. Then, in a disused cabin, Theo finds something impossible: a photo of herself as a child. A photo taken at Idlewood.

I’ve been here before.
Theo has almost no recollection of her earliest years, but now she begins to piece together the fragments of her memories. Someone here has a shocking secret that they will do anything to keep hidden, and Theo is in terrible danger. Because the Daltons do not lose, and discovering what happened at Idlewood may cost Theo everything.