Distracted by Ben and Gwen quarreling, Max almost hits a young camper on the road. They take the boy back to his camp, Camp Opinicon, only to find no one there. As they investigate the premises, they find two more children, twins, who are hiding from something that caused the camp to become deserted. Max is captured by tendrils while he investigates, prompting Ben and Gwen to split up. While Gwen leads the campers to safety from fungal mutants, Ben attempts two failed rescue missions, getting captured on the second. In trying to escape, Ben unlocks a new alien form, a plant-like alien named Wildvine; however, even Wildvine cannot defeat the brain that controls the fungal creatures. Fortunately, Ben drops an antifungal drug onto the brain and causes it and its minions to wither. Ben and Gwen spread more of the antifungal powder on its tendrils and save the camp.