High Stakes by Freya Barker

When her sister, Pippa, goes missing, Nella Freling tells her boss she’s taking time off from her job as a research librarian, hops in her sensible van, and heads south of the border to Montana. However, local police don’t seem too concerned about a missing woman living in her motorhome. So Nella will have to look for Pippa by herself, unless she can convince a highly recommended tracker to help her, but sadly the rude and angry cowboy won’t even listen to her at first.

But Nella can be persuasive.

The first time High Mountain Tracker, Fletch Boone, laid eyes on Nella, her ass was stuck in his grocery cart. The next time was at the ranch; she was wearing mud, head to toe. But when he catches sight of her a third time, hanging off a cliff, he can’t turn his back again. What Nella lacks in survival skills she makes up for in sheer determination. Unfortunately, neither of those is enough protection when bullets start flying.

Fletch has no choice but to jump in before the woman gets herself killed.
And that would be a damn shame.