American Gods vs. Baba Yaga in this Russian-inspired contemporary fantasy Spring's Arcana, by New York Times bestseller Lilith Saintcrow.

 

Nat Drozdova is desperate to save a life. Doctors can do little for her cancer-ridden mother, who insists there is only one cure--and that Nat must visit a skyscraper in Manhattan to get it.

 

Amid a snow-locked city, inside a sleek glass-walled office, Nat makes her plea and is whisked into a terrifying new world. For the skyscraper holds a hungry winter goddess who has the power to cure her mother... if Nat finds a stolen object of great power.

 

Now Nat must travel with a razor-wielding assassin across an American continent brimming with terror, wonder, and hungry divinities with every reason to consume a young woman. For her ailing mother is indeed suffering no ordinary illness, and Nat Drozdova is no ordinary girl. Blood calls to blood, magic to magic, and a daughter may indeed save what she loves...

 

...if it doesn't consume her first.

 

This is the way to the Dead God's Heart.