After learning Nen and becoming a true Hunter, Gon returns to Whale Island with Killua. When he arrives, Mito has a box for him. She was told by Ging to give this box to Gon once he became a Hunter. However, it appears that the box cannot be opened.

After landing a punch on Hisoka, Gon returns the tag from the Hunter Exam. Hisoka is ecstatic to see Gon's development and uses his own Nen to attack. Gon is scared, but he recklessly continues to attack! Will he emerge victorious?

Gon and Killua begin training in Hatsu, the culmination of everything they've learned about Nen. And finally, Gon challenges Hisoka to return the favor from the Hunter Exam. "I'm going to give the tag back to Hisoka while punching him in the face!"

Gon has fights against Gido and Riehlvelt coming up. He's still mad about what they did to Zushi. Gon is able to withstand Gido's attacks and overwhelm him in battle. This causes Hisoka to smile.

After two months, Gon and Killua are finally allowed to practice Nen again. That's when Gido, Sadaso, and Riehlvelt appear before them and tell them to fight them in the arena. Gon and Killua refuse, but Killua finds Sadaso's behavior to be very suspicious.

Kastro has used his ability to create a clone of himself with Nen to sever Hisoka's arm and take an advantage in the fight. However, despite losing both arms, Hisoka appears to be perfectly calm. Kastro loses his cool and attacks Hisoka.

A month has passed since Gon was seriously injured, and Hisoka and Kastro are about to fight in Heavens Arena. Kastro was able to knock Hisoka down in the past and sounds very confident in his interview. Hisoka appears unperturbed by the upcoming fight.

Gon faces the Nen user Gido in his first 200s Heavens Arena match. Gon uses Ten to protect himself, but he soon finds himself on the defense against Gido's Dancing Tops. As Gon desperately tries to find a way to fight back, he makes a bold decision...

After reaching the 200th floor, Gon and Killua run into Hisoka's barrier of Nen. They ask Wing to use the violent method for activating their Nen potential. As the deadline for registration draws near, they begin training in one of the four major principles of Nen, Ten.

As Wing explains the tenants of Nen to the boys, Killua believes that they aren’t being told the whole story. After a meteoric rise from the 1’st floor to the 190’s, they finally get their chance to register for a fight on the 200th floor. But just stepping off the elevator, the murderous intent is unlike anything they have experienced.

Gon and Killua have arrived at Heavens Arena, where opponents get stronger as you ascend the tower, to train and make money. Both of them are immediately advanced to the 50th floor after their initial battles on the 1st floor. There, they meat Zushi. When Killua faces off against Zushi, he has no difficulty at all, until Zushi uses a strange technique reminiscent of what Illumi used...

A letter from Gon arrives at Whale Island for Mito... (A recap of everything that has happened.)

Canary guides Gon and his friends to the butler office. There, they meet the butler Goto, who challenges them to a coin game so he can determine if they are worthy of being Killua's friends. After winning the game and reuniting with Killua, Gon now looks ahead to his next objective...

With help from Canary, who is concerned about Killua, Gon and his friends are getting closer to the mansion. However, Kikyo tells them that Killua cannot see them as he is in solitary confinement. Meanwhile, Killua has been summoned by Silva and asked if he wants to see his friend? Killua answers truthfully, and he is allowed to go see his friends...

Gon and his friends have decided to pass through the Trial Gate to see Killua. First, they must train in the servants' residence until they can open the gate. Meanwhile, Killua has learned that Gon and the others are here to see him. Gon, Leorio, and Kurapika are able to open the gate after completing their training, but the apprentice butler Canary stands in their way.

After arriving in the Republic of Podokea, Gon, Leorio, and Kurapika board a tour bus to Kukuroo Mountain, where Killua lives. However, they're blocked by a massive gate. Anyone who attempts to enter through the side door is eaten by the watchdog. Gon tells the guard that they are friends of Killua and asks to be let in.