When Dai Shi beat up the Rangers profusely in a big showdown and sequestered R.J., the Rangers were left Master-less. R.J. told them they knew what to do, which was to go back to basics, which led them back to the Pai Zhuq Academy room where Dai Shi was kept. The Rangers noticed the masters' animal spirits etched in the wall and wondered where the gorilla, penguin, and antelope masters. They were greeted once more by their fallen teacher Master Mao. He sent them to the Spirit World to be trained by three fallen masters. They put them through tests, Master Lope sent Theo to a dimension where he had to surpass his ego and embarrassment in singing karaoke in front of a large audience. After complaining and then realizing what he had to do, he had passed the test and granted the Claw Boosters, Jungle Master mode, and Antelope animal spirit zord.
Theo later could summon the Bat Spirit Ranger when needed. When Lewin came to town, he realized he was jealous of his lazy but talented brother. Lewin was mistaken for Theo and captured by one of the Phantom Beast Generals. Theo saved his brother and he discovered his true identity and their bond became stronger. Theo was discouraged in revealing his true feelings to Lily when she told him they were only friends but Fran clarified he never really asked her on a date. After the final battle, he finally asked her on a date and she accepted.