It’s bad enough that everyone in the world of Avatar: Seven Havens is living in a post-apocalyptic wasteland, but Ellora is now officially on the brink of collapse. After the first three episodes of Book One: Survival introduced the new Avatar and her long-lost twin, episodes 4, 5, and 6 — released Friday — turn the Haven into a pressure cooker of civil unrest, bandit attacks, government secrecy, and the strange fear-based infection people begin calling “The Anomaly.”