Hyuga Jun has a system that allows him to become stronger by treating people's illnesses. He uses this system to help Naruto, who is struggling academically. Hyuga Jun diagnoses Naruto with an imbalance of Yin and Yang, and parasites (the Nine-Tailed Fox). After a treatment of medicine, Naruto is able to perform the Clone Jutsu successfully. The Nine-Tailed Fox, weakened, vows revenge. Later, Hyuga Jun treats another patient with a unique condition.