Frozen x Little Mermaid: The Crimson Shadow of War (Book 3 & 4)

Anna and Elsa are about to lose everything they hold dear as war is coming to Arendelle. 5 months after Frozen 2, a tyrant rises with Anna's determination and powers as dangerous as Elsa's. The two sisters must reunite with their allies to save their kingdom and stop the biggest threat they have ever faced. Meanwhile, a familiar cunning Prince returns to stir up trouble.