Knights of Glass — Katharine Giles

After Archer and Aradia accept an invitation to meet King Herron, the ruler of Sundari, they are sent to a remote island near the sea. Here they'll rendezvous with the Kantor Warriors who will escort them to the glass city. Archer isn't happy with the remote destination and is further confused and stunned after their arrival when three black horses, their riders dressed in black, descend from the sky to meet them. He rapidly learns that a terrifying ride on the kantors is only his first surprise.

After Archer and Aradia arrive in the city, the Captain of the Kantor Warriors, drops them off at the glass pyramid where they meet Keeri, Sundari's crystal master. While Keeri gives them a tour of the kingdom in her crystal ball, she tells them Sundari is an animal refuge. But when images of woolly mammoths appear in the crystal ball, Archer and Aradia learn Sundari is more than a refuge. It's a sanctuary for every animal that's ever lived in Skye's galaxy.

After seeing images of this unique kingdom, Archer is eager to learn the reason for King Herron's invitation. However, that information has to wait for King Herron has received unexpected news and needs their help. Visitors from the stars have landed and set up camp in the wilderness. King Herron doesn't know who the Star Warriors are or why they've come and worries they'll bring chaos and destruction to his kingdom.

King Herron asks Archer and Aradia to travel to the Star Warriors' camp and invite their leader to the city to meet with the king. Eager to see the country (and possibly a few animals along the way), Archer and Aradia eagerly accept the task. Wyndryder and her Kantor Warriors escort Archer and Aradia into the wilderness where they'll join the River Warriors for the last leg of their journey. However, because King Herron wants Archer and Aradia to understand why he fears for his kingdom, he's told Wyndryder to stop at Lokwanda and show Archer and Aradia the living dinosaurs.

After they join Stryker and his men, Archer and Aradia enjoy a swim before they retire. But the charm Aradia finds on the river bottom changes everything after Stryker tells her the charm identifies the Star Warriors as enemies of the Mother Star. The danger escalates after Archer and Aradia learn they're on their way to meet the leader of the star fleet that kidnapped Volka's wife and child. Do they have the skills to save Volka's family or will Sundari's uninvited guests escape and wander the universe with their prisoners?