Two Princes of Summer : Whims of Fae bk.1
(Book)

After her mother's suicide, Scarlett's grief consumes her. When an otherworldly stranger offers her a release from her pain, it's too tempting an opportunity to resist. She's lured into Faerie and sucked into a royal battle as two fae brothers prepare for the Battle of Heirs where the winner earns the right to the throne. Human emotion fuels fae power and Scarlett's is the most potent Cade has ever tasted. He's certain she is the key to defeating his brother Raith. But Raith has surprises of his own, and Scarlett fits perfectly into his devious plan.