Lesson 1: Niki-Niki! Fierce Beast-Fist

'''Niki-Niki! Geki Jūken''' (ニキニキ！激獣拳) is the first episode of Juken Sentai Gekiranger.

Synopsis
On a lunar eclipse that occurs every 500 years, the Kenma Bracelet must be sealed at area surrounding the Jūken Life Tree. But, Geki Jū Leopard-Ken user Miki Misaki encounters a wild child named Jyan Kandou before she is attacked by a group of Akugata martial artists led by Rin Jū Mantis-Ken user Makirika, who steals the Bracelet. Then, the leader of Rin Jū Hall, Rio, obeying the souls of the long dead founders of the Rin Jūken style, starts their plans to conquer the world by first amassing Rinki energy from the terror inflicted on humans. However, the Grand Master of the Geki Jūken style, Kensei Xia Fu, along with Miki have been prepared for this coming battle and were training two young fighters: Geki Jū Cheetah-Ken practitioner Ran Uzaki and Geki Jū Jaguar-Ken user Retu Fukami. Jyan joins the other two warriors in forming the Gekiranger team. However, they face Makirika, now a Beast-Man after absorbing enough Rinki. Though Jyan manages to defeat Makirika with Geki Jū Tiger-Ken, the Beast-Man soon grows into a giant.