The show starts with Keiko asking Yusuke's mom, Atsuko, when Yusuke is coming back. Yusuke's mom says that Yusuke said something special was supposed to happen after 6 months. Keiko is walking when someone starts walking toward her. It turns out to be Yusuke back from his "Evil Boot Camp", as he calls it. Keiko's buying some milkshakes while Kuwabara discusses what Yusuke did at Genkai's and he says that he'll be having nightmares for the next four years. Keiko overhears the last bit of them talking and Yusuke says Kuwabara said that he wanted to see a movie. They walk to the theater when Yusuke says they have to go buy some guy stuff. Kuwabara asks what he has to buy and Yusuke says that they were being followed. The two lead them to an alley and Yusuke performs one of his new moves he learned at the training. The Shotgun, an attack that shoots the enemy with many bullets made from Spirit Energy. The attack annihilates the 5 enemies and Kuwabara senses another inhuman person near them. They chase the creature into Botan who hits him with a bat. Botan says that Yusuke has another case which ticks off Yusuke cause he just got back from Genkai's training. Botan convinces Yusuke by telling him that if he does not go, the town will be destroyed by violence crazed zombies. The boys that were following Yusuke and Kuwabara actually had a bug in them which is called the Makai Insect. These bugs turn everyone into violent and power-hungry zombies. They can only live outside Spirit World with a special whistle. The demons in control of the whistle will give it up if they are let into the Human World. However, Koenma wants to send Yusuke in through a small hole in the barrier, which is what is keeping the demons with the whistle at bay. The two realize that Kuwabara just heard the whole thing and he decides to tag along. They enter through the hole in the barrier, which also happens to be a glowing hole in the middle of a floor in a basement, and are immediately attacked by a horde of hungry demons coming up through the ground. Then, through the hole Yusuke and Kuwabara came through, came a two bright lights, one blue and one red, which scared the demons away and the balls of light land on a tree and form into Kurama and Hiei. Hiei says that if Kuwabara and Yusuke can't last against the weak demons that had attacked the two boys when the first came through the barrier, they are in trouble. Hiei says that he and Kurama will do the fighting in the castle and says that humans are weaklings, but the comment is mainly directed towards Kuwabara. Kuwabara does not take it to well, so Kuwabara tries to hit Hiei but Hiei is to fast. Hiei says that he will get his revenge on Yusuke for defeating him, who retorts that he will take Hiei on if they make it out alive. The four beasts, hiding in the tower in their castle, do not believe that the group will make it past the gate. When Yusuke, Kuwabara, Kurama, and Hiei enter the gate, a one-eyed, purple bat-like creature appears and gives them the Gate of Betrayal Trial. The trial is that the cieling comes down on top of the four boys of the four, who have to hold it up. But there is enough room for only one person to make it past and that one is worthy to enter while the others are crushed under the cieling's weight.