Plot
The first half of this arc has our heroes arriving on the supposedly deserted planet M2 as they continue on their quest for the Black Star Dragon Balls. However, they find themselves caught in a trap by the planet's inhabitants, mutant robots, and that Giru was deceiving them all along. Pan manages to escape and later rescues Son Goku who does battle with the robotic group of commandos known as the Mega Canon Sigma Force and their leader General Lock (DUB: General Rilldo). However, both he and Pan are captured again and taken to Doctor Myuu for studying. Giru has a change of heart though and manages to rescue the trio thanks to a clever plan by Trunks. It is then that we see Myuu's true creation, Baby, who breaks free from his containment after being revived but stopped by the three saiyans. However, as a defeated and injured Myuu escapes, a piece of Baby scattered remains jumps onto his skin, later busting out of Myuu and reforming into his original state. Baby tries two more times to kill Goku, Pan and Trunks but fails though he manages to escape to Earth.
This is where the second half begins, as Baby begins to spread his infection across the planet and growing. He soon runs into Son Goten and takes over his body, then Son Gohan before finally fighting Vegeta and making his body his permanent host. Goku, Pan and Trunks arrive back on Earth only to find everyone, even their own family, against them due to Baby's mind control (save for Majin Buu, who's body is immune to Baby's eggs and Mr. Satan, who hid within Majin Buu). Goku confronts Baby, but his kid body isn't powerful enough to reach the levels needed to beat Baby who gains more power from Son Gohan, Son Goten, Trunks, Bra, and the rest of the world, and thus is beaten and nearly killed if not for Kaiōshin/Kibito rescuing him at the last minute. Baby then goes to use the Dark Star Dragon Balls to wish for new planet, Tuffle, and begins to move all his mind controlled subjects to it. Among the others who were possessed by Baby were Videl, Chi-Chi, Dende, Mr. Popo, Kuririn, Android 18 and Marron. Dende handed the Black Star Dragon Balls over to Baby, so he could wish the planet Tuffle back, thus sealing the Earth's fate.
While on the other plane, Goku is accidentally dropped into a weird dimension where he must play for his life. After escaping from that and arriving on the Kaiōshin planet, he begins special training needed to regrow his tail (since it was his power source when was a kid) but the process is sped up once Goku sees Pan in trouble. Goku is then transported to the Tuffle planet, tail and all, and tries out his power. Despite the power of his maximum Super Saiyan 3 level, he still couldn't evenly match Baby, however he soon enough received assistance from the Earth itself, as its full view in the planet's orbit provided just the right kick for Goku. He becomes a gold colored Oozaru (Giant Ape or Great Ape), however he goes on a rampage since he can't control himself in that form. It isn't until Pan confronts him and pours her heart out to him that Goku is able to reach the next and final level of transformation, Super Sayian 4! Goku pounds on and almost defeats Baby, but the villain gets assistance from the mind controlled Bulma when she creates a device that allows him to increase his power to that of a Golden Oozaru, evenly shaping the battle as Goku and Baby eventually double KO one another. While this is going on, Old Kaiōshin finds a way to get rid of the infection from a special water in the lookout point and sends Kaiōshin/Kibito to fetch it and frees Trunks, Goten, and Gohan. Because of this, Gohan and the others show up on the scene to help Goku defeat Baby, however Goku knows that neither Gohan or Goten and Trunks' fused counterpart Gotenks would be strong enough, hence they all must give him their power. Uub (who was eaten thanks to an attack thrown back at him) attacks from the inside of his stomach while the freed sayians take their shots at giving Goku their ultimate powers, along with Pan who joins in as well. Just as Baby spits Uub out, Goku finishes collecting the needed power to restore his power back to full, thus a couple kamehamehas and an energy blast later, Baby's down for the count. Severely weakened, Baby leaves Vegeta's body and tries to escape in a spaceship. But Goku blasts it with a Kamehameha, directing it into the sun and killing Baby for good.
However, the crisis is not over. While everyone is freed from the infection, the second wish on the Black Star Dragonballs increased Earth's countdown destruction. However, Goku comes up with a plan to move anybody left on Earth to the Tuffle planet. With the help of his family, friends, and the Kais' they manage to pull it off. Yet Piccolo decides to stay behind as his death would void the power of the Black Star Dragonballs and keep them from being used again. Piccolo gives every bit of power he can to Goku for him to save a little boy, has one last emotional talk with Gohan, and dies a dramatic death as Gohan screams his name in sadness. Goku then uses the Namek's Dragon Balls to wish Earth back to normal and everybody back on it. Finally closing out this arc before moving onto the Super Android 17 Saga.