In the Great Journey of Karate 4, Tatsuya Naka, one of the world's leading martial artist, visits Okinawa again. He meets with Okinawa's leading Karate-Ka who he trained with in the previous Great Journey series. He explores what Karate was like in Okinawa, what was preserved, lost, or changed between Okinawa and mainland Japan Karate. With that information, he explore deeply into mysteries of techniques left behind by Gichin Funakoshi.