While Jaco takes a ramen break, he accidentally loses custody of the evil criminal Watagash, who he had just captured. On Earth, Gohan and Videl learn that Mr. Satan is starring in a new superhero film with superstar Barry Kahn as Great Saiyaman! Gohan’s family visits the set and Mr. Satan introduces them to popular idol Cocoa Amaguri, playing Saiyaman’s love interest. Barry Kahn then appears and attempts to flirt with Videl, but turns him down in front of the film crew. Gohan later decides to serve as Barry’s stunt double to impress Pan, and thinking he will only hurt or embarrass himself, Barry allows it. But Gohan uses his powers and amazes everyone on set, with the director immediately hiring him as the official stunt double. Later on his way home, Gohan intervenes as the Great Saiyaman against a pair of bank robbers from his past, one of whom suddenly becomes extremely stronger after being infected by Watagash, but is still defeated by Gohan. Though Bulma covers for him when the film crew nearly deduced him to be the real Great Saiyaman, Gohan’s secret is found out by the film’s co-star Cocoa who blackmails Gohan into flying her around the city. But the two are attacked by Jaco as he assumes Great Saiyaman is Watagash’s new host!

Prologue

Somewhere in space, Jaco sits at a ramen shop enjoying a warm, delicious meal. The ramen shop owner questions whether it is wise for him to stop like this, since he is on the clock, but Jaco insists everything is fine. He has just caught and sealed away the fiendishly evil criminal Watagash in a special container, which is sitting in his ship. The owner is shocked, but Jaco explains that there’s no way Watagash could escape. As Jaco sits eating ramen, Watagash breaks the containers glass and escapes off into space.

Part A

On Earth, Videl and Gohan are shocked to see a commercial for the upcoming film “Great Saiyaman vs Mister Satan”, starring superstar Barry Kahn as Great Saiyaman, popular idol Cocoa Amaguri as his love interest, and Mr. Satan as himself. On the phone with Videl, Mr. Satan explains that Barry approached him with the offer of making a film together. Videl cannot believe it, as Satan seems to really be into this acting thing.

As Barry arrives on set to begin shooting the movie, his car is surrounded by reporters. One reporter asks him why he agreed to playing such a minor, and now largely forgotten, hero like the Great Saiyaman. Barry thinks that the contrast between a has-been like Saiyaman and a star like him is precisely what makes it so interesting. After making it onto the set, Barry meets with the assistant director and insists they update the commercial with the movie’s new title, that he came up with himself: “Barry Kahn in Great Saiyaman vs Mister Satan!” They think that’s too long, but Barry doesn’t care; this is his film and they better not screw it up. Suddenly Barry is called to wardrobe, and he heads off.

Meanwhile, Gohan, Videl, and Pan have arrived on set and Satan is showing them around. Gohan wishes they could have shown all this to his father, who Satan notes is off training, when suddenly Cocoa Amaguri runs up. Satan introduces them to her and starts telling her that while Gohan might not look like much, he is actually the real… but Videl quickly stops him from spilling the beans about Gohan being the Great Saiyaman; that might cost him his academic job! Barry then shows up (in costume) and tries to flirt with Videl, but she’s not interested. Barry can’t believe, and neither can the film crew watching on. Gohan says she could have gotten one, but Videl says she didn’t need one. Besides, she thinks Gohan is much cooler.

Filming has begun, and Gohan is surprised that Barry is not doing his own stunts. Satan says he wants to, but no one wants a celebrity of his stature to get hurt. Barry’s stunt double takes his spot in front of a tank, but just as the director is about to call action Barry stops them, suggesting they change the script: rather than dodging a tank, his stunt double should jump on top of it… without using wires. Everyone thinks this is absurd, but Barry insists, until finally Gohan steps in and volunteers. Barry thinks he is doing this to become popular with the ladies, but Gohan figures that if he is in this movie, Pan will enjoy watching it when she grows up.

Gohan puts on the stuntman’s Saiyaman costume and takes his spot on the set. Barry watches in amusement, sure that he will hurt himself and make Videl sorry she embarrassed him earlier. As the tank speeds toward him, Gohan performs a superhuman leap onto the tank (amazing everyone), pulls out the driver, and then finishes off with a classic Saiyaman speech.

Part B

Standing outside the studio, Gohan thinks of what a mess he has gotten himself into. He thinks back on what transpired after shooting that scene — The director rushed over wanting to officially sign Gohan as the new stuntman, but Videl was all for it: in that suit nobody will be able to tell it’s him… and seeing him as Saiyaman again got her excited thinking of the old days. Mr. Satan also asked him to do it, because he can’t risk anything going wrong.

Walking home, Gohan worries about memorizing the script, but then spots a bank robbery in progress. Kuririn (as part of his police job) is facing off with two crooks equipped with military technology. Gohan changes into the Saiyaman costume he is carrying and smashes through the wall, knocking Kuririn out in the process. The two crooks remember Saiyaman: they were the ones he and Videl caught back when Saiyaman made his debut! This makes Gohan nostalgic, but the crooks want payback after being stuck in jail this whole time.

Unbeknownst to everyone, Watagash appears crawling across the floor and hops into one of the robbers boots, infecting him. Meanwhile in space, Jaco confirms that Watagash has fled to Earth. The robber suddenly becomes enraged and knocks his partner out of the way, and then rushes at Great Saiyaman. The two exchange blows up in the air, but he’s still no match for Gohan, who knocks him out and prepares to finish him off with a Kamehameha. However, fearing collateral damage with everyone standing around watching, he opts for a small “Great Saiyaman Beam” instead. As the police haul off the robbers, Kuririn asks Gohan why he is going around dressed up like that at his age, but he insists he’s not Gohan, but Great Saiyaman. With the other police gone, Gohan admits it is him, but he has Videl’s approval!

The return of Saiyaman makes the news, and while reporters assume it was a promotional stunt by Barry, everyone on set has already guessed it was really Gohan. However, Bulma arrives and claims that a spare Saiyaman suit she made for the film was stolen from her lab, and that this thief must have been the one who stopped the robbery. With Gohan’s secret still safe, Bulma asks him not to get carried away… but their private conversation is overheard by Cocoa.

After the day’s filming, Cocoa approaches Gohan and asks him to help her practice her lines. She even wants him to fly her home, and when he objects, she reveals she heard him talking to Bulma and knows he was really the one who stopped the robbery. To keep her quiet, Gohan agrees to fly her home, dressed as Saiyaman. Enjoying the scenery, Cocoa asks Gohan to take the long way around so she can see the cityscape at night.

As the two enjoy their view of the city at night, they suddenly run into Jaco standing atop his spaceship. Jaco is convinced that Saiyaman is Watagash’s new host, and before Gohan can say anything Jaco fires his ship’s cannon to destroy him!