High Lonesome by Tanya Chris

Joe doesn’t live on top of a mountain because he loves people. A late summer snowstorm is the perfect chance to send his customers down to lower altitude and enjoy a few days of solo strolls and fireside naps.
Tanner’s not staying at a high-altitude hut to admire the scenery. He’s got a date to keep with the sort of person you don’t want to disappoint, a date that’ll result in him earning some much-needed cash in exchange for what’s left of his self-respect. But that’s OK. He gave up on self-respect when he picked up the needle anyway.

Pyotr didn’t drop into a blizzard to rescue Tanner or to drag Joe back down to the real world. His mission is a lot colder than that. People are only pawns, and spies are only heroes to those who don’t know them.
Hermit, addict, spy. Three men, one snowstorm, zero reason to trust. And someone’s coming …

Content warning: this book contains on-page heroin use and detox. A brief argument follows the reveal of a character’s HIV status.