Commander ApeTrully receives a message that an unknown animal king wants to join Big Green. However, it is a trick and they are ambushed by Bearstomp and his Bears. When First Squad fights the bears, the Zebra brothers capture ApeTrully.
Lin Chung then tells the tale of the Spirit Cave, and he, Mystique Sonia and Mighty Ray go to it, becoming their inner animals (A panther, a swan and a bear, respectively).
Even if they find Commander ApeTrully, they also would have to fight Twin Masters who was also involved in Commander ApeTrully's capture, as well as their toughest opponent yet, Commander ApeTrully (because Twin Masters blasted him with a huge amount of chaotic energy).