Will-o'-the-Wisps and the May Queen. Book 3. Silver Dust

Eru is tormented by vague doubts about what is happening in the world of Pure Ones and Demons. She understands that behind what is happening lies a terrible secret connected with the Sky Tower floating in the sky.
Urs experiences hitherto unknown feelings towards Princess Sabrina, but he cannot decide to admit it to her.
Meanwhile, Aurelia, realizing that her earthly term is coming to an end, decides to put an end to the long and senseless war between the Pure Ones and the Demons. For this, she plans to help Eru escape to the Demon Kingdom of Oscuria, to the Сourt of King Ephil.
And Ephil himself receives a message...