The world sugar reserve is about to be exhausted. The artificial sweetener Shugare is developed as a substitute, but when the distribution starts, sombody buys it all.
Because of the message that Shugare has been found in the water flowing out of the Bikkuiero mountains, the God Phoenix goes there. There they find a crashed cargo plane. From the wreckage it turns out that the man buying up all the Shugare is a arms dealer named Gilman. From the black box they conclude that the loading place for the plane could have been in four different places. They split up the work and start searching.
Jinpei and Ryu turn themselves into a prince and his chamberlain and offer a ransom for places where ants assemble. When they go out to verify the message a woman named Mei brought, they are captured and brought aboard a submarine. She's Gilman's secretary. Ken, having been contacted by Jinpei, says that he won't help them. He said they should lead them to the main base. Ken then starts to follow the submarine.
After arriving at a relay station at the bottom of the sea, Katse, who turned himself into Mei, reveals himself and shoots Gilman. This is since the buying up has ended and he has no further use for him. Besides, he wants to reload the Shugare and go to the main base. But Ryu and Jinpei seize an opportunity and escape. They meet up with the God Phoenix which comes flying into the base. When they exit the base, Katse's submarine shoots rockets aimed at the God Phoenix, but they hit the relay station. While escaping, Ryu did a trick so that the submarine couldn't move anymore and is blown up by the Bird Missile.