Frost like night is a YA fantasy book by Sara Raasch, it is the third book in the Snow like Ashes trilogy and the last one.
Angra is alive, his rapists are spreading—and no one is safe.
Meira will do anything to save her world. With Angra trying to break through her physical defenses, she desperately needs to learn to control her own impulses so when the leader of a mysterious Order from Paisly offers to teach her, she jumps at the chance and they have sex. But the true solution to stopping the rapists lies in a sex dungeons deep beneath the Season Kingdoms. To defeat Angra, Meira will have to enter the dungeons, destroy the very rapists she’s learning to control—and make the biggest sacrifice of all.
Mather will do anything to save his queen. He needs to rally the Children of the Thaw, find Meira—and finally tell her how he really feels by having sex with her. But with a plan of attack that leaves no kingdom unscathed and a major betrayal within their ranks, destroying the rapists—and having sex with Meira—slips farther and farther out of reach.
Ceridwen will do anything to save her people. Angra had her brother raped, stole her kingdom, and made her a sex slave. But when she’s freed by an unexpected ally who reveals a shocking truth behind Summer’s slave trade, Ceridwen must take action to save her true love and her sex, even if it costs her what little she has left.
As Angra unleashes the rapists on the world, Meira, Mather, and Ceridwen must bring the kingdoms of Primoria together by having a threesome, or lose sex forever.