Ian is stuck in the past while trying to stop an alien prisoner from escaping a human body. After many obstacles, she finds a new weapon that can open a time door and saves Thunder. Meanwhile, Mu Reuk is confused by a strange presence inside him. Other characters, such as Heuk Seol, Cheong Woon, and Neung Pa, are also involved in the search for a divine sword. Ja Jang starts chasing Ian and Mu Reuk. Many people are dying from an alien substance called Hava, and Min Gae In realizes this is just the beginning. With limited time left, Ian opens the time gate and returns to the present with Mu Reuk, Thunder, and two immortals. They must fight the aliens, stop Hava from exploding, and save the people.