Aboard the Ragna Rock, the Dimensional Engine is destabilizing due to the presence of the blue Chaos Emerald, Sonic and all of his friends being evacuated via Boom Tube courtesy of Cyborg and Green Lantern, and Superman and Wonder Woman restraining Darkseid to stop him from regaining control of the Engine. The latter three are hit with a burst of flames from the Engine's mouth as Flash retrieves the red Chaos Emerald, remarking that he at least got one of them. As Green Lantern encases himself and the other Leaguers in protective bubbles to keep them safe from the malfunctioning Engine, Cyborg plugs the red Emerald into his arm cannon, planning to make an escape tunnel; upon Wonder Woman asking if it's a wormhole or blasting their way out, he answers that he has no idea which, but they'll find out. He blasts into the wall of energy, creating a portal that the League runs into; it sends them safely onto Sonic's Earth. The Ragna Rock continues to float in the sky, crackling ominously with the blue Emerald's energy swirling around it as the League looks up at it. Green Lantern notes that he's never felt energy reactions like the ones on the Ragna Rock and remarks his construct wouldn't have lasted any longer. Batman himself notes that Darkseid's Dimensional Engine is destabilizing the planet, but Superman believes the Ragna Rock is affected the most and believes it'll occupy Darkseid's attention. He asks Cyborg for insight, and he agrees with Batman: the fabric of space-time is badly affected by the incident, and he can't get them a clear path back to their world, with the only stable thing being the Emeralds' resonance-- a statement that gets him thinking. Wonder Woman asks if he has a plan, but he corrects that it's a hypothesis-- one he can't test until the other five Emeralds are obtained. Flash says they've already narrowed down the search for the gems, so they can end this quickly. Superman adds that they should keep an eye out for anyone in need, as this world needs them even more now without Sonic and the others to defend it.
At the Water Palace, Blaze the Cat is battling Parademons and Female Furies Stompa and Mad Harriet, who are searching for "Darkseid's prize"-- the purple Chaos Emerald clutched in Blaze's hand. As Harriet pounces on the cat, Wonder Woman storms in and prevents the attack with her Lasso of Truth, defeating the Furies and Parademons. In the moment of peace, Diana and Blaze-- both warrior princesses in their own right-- introduce themselves to each other, with the latter being grateful for her help and voicing her determination to protect her friends and their homes before revealing that the Furies and Parademons were after the purple Emerald. Wonder Woman also reveals she and the League hope to gather the Emeralds and use them to banish Darkseid's forces and return Sonic and his friends home. Blaze is happy to part with it, saying that while she wouldn't do so in any other situation with anyone else, she sees Wonder Woman's "valor and nature", but she also reminds her that they should deal with the threats at hand first-- a sentiment Wonder Woman agrees with.
Between Westopolis and Central City, Batman has engaged Metal Sonic - who holds the white Chaos Emerald - in a silent battle on Radical Highway and is chasing him down aboard the Batcycle. As Metal Sonic boosts up one of the bridge cables, Batman fires his grappling hook at the robotic doppelganger, grabbing his foot with it. He gets off the Batcycle as it continues driving and is carried along as Metal Sonic flies off; he throws a flurry of Batarangs that are easily deflected. As Metal Sonic lands on the ground, he looks up to see Batman gliding above him, but is surprised to find it was a distraction as the Batcycle slams into him, causing him to lose grip of the white Emerald and tumble smoking to the ground; simultaneously, Batman retrieves the Emerald. At the Lava Mountain Castle on the Lost Hex, Flash encounters Virman Vundarbar, one of Darkseid's elite, alongside the Deadly Six, the former loudly boasting about controlling them using the Cacophonic Conch while holding the yellow Chaos Emerald, which he intends to deliver to Darkseid. Flash quickly points out that it was not a good idea to tell him how he's controlling his new minions and steals the Conch from him, freeing the Deadly Six, most of whom proceed to beat Vundabar to a pulp. Despite being grateful for Flash's aid, Zavok demands that he relinquish the Emerald so they can "wage war on the world below", but he refuses and zips off, causing Zavok to groan that he's just as annoying as Sonic. Elsewhere, Flash jumps off of the Lost Hex and onto one of the mountains surrounding Never Lake to return to the Earth; amazed by Sonic's planet, he calls the League to tell them he has the yellow Emerald, then mentions that Empire City apparently has an 8-lane highway loop-de-loop that he has to experience despite time being short, promising he'll be quick.
Amid the Egg Fleet, a cackling Dr. Eggman is eager to continue his plans for conquest uninterrupted now that Darkseid is hoist by his own petard and Sonic and his friends are missing. But he soon finds himself confronted by Superman, who easily destroys his fleet and confronts him in his battleship, pointing out that it's too early for Eggman to take advantage of the crisis to betray them and continue his evil ways after having just helped them confront Darkseid. Responding that it's best to "strike while the iron is hot", Eggman attempts to subdue Superman with the Egg Emperor mech, but its lance merely breaks against the nearly-invulnerable palm of the Man of Steel, after which he tosses away the mech's shield and rips open the cockpit. Visibly disappointed in Eggman, Superman both tells the mad scientist that he'll never understand the ambitions of villains like him and reminds him that his world is in danger, asking if he has any concern for his own self-preservation; after muttering that Superman, as a "tourist", shouldn't be trying to moralize him, Eggman reluctantly gives the hero the location of the Chaos Emerald he stole. Eggman begins to request that Superman at least use the elevator instead of wrecking his battleship, but Superman disregards his request by smashing through the floor, drawing the villain's frustration and ire; shortly after, Superman retrieves the cyan Chaos Emerald, alerting the League of his success.
In the Luminous Forest within the Mystic Jungle, a group of Wisps -- with Yacker in particular carrying the green Chaos Emerald -- is being chased by Granny Goodness, who uses her scepter to encase some of them in bubbles. The other Wisps hide under a tree root with the Emerald as Granny approaches them, declaring that she plans on draining them of their energy to find a good use for it. She's stopped, however, by a barrier construct from Green Lantern, who requests that "Grandma" stop traumatizing the aliens. Granny fires a beam, saying she's been researching how to deal with the Lanterns who have been telling her what to do; despite trying to repel it with a blast from his Ring, the beam slams Green Lantern into the tree the Wisps are hiding in; they gather around him as he attempts to convince them to get somewhere safe, then transfer themselves into his Ring. While momentarily confused, Green Lantern soon understands what they're doing, then recites an altered version of the Green Lantern oath to fit with the situation as he blasts Granny with a multi-color beam powered by the Wisps' energy. As the Wisps exit his Ring, Green Lantern thanks them, saying Granny shouldn't bother them anymore. Yacker hands him the green Chaos Emerald as he proclaims that with it, he and the other Leaguers hope to fix everything somehow. He warns them to alert their friends to hide for the time being as he leaves, but afterward, he notices that his Ring is low on power, with the Battery that charges it still on the Watchtower. However, he comes up with the idea of plugging the green Emerald into the Ring, which supercharges it, much to his exhilaration.
The League gathers at Tails' Lab soon after, and with all of the Emeralds but one in their possession, Cyborg says that he now has a solid read on how the Emeralds interact with each other and a way to deal with their problem. He mentions that space-time and subspace are too distorted by the Dimensional Engine for them to use a Boom Tube to leave, but he can use the power of their Emeralds to send them to their home dimension; the resonance between those Emeralds and the blue one aboard the Ragna Rock will create a conduit that should let Sonic and the others make contact. Flash asks Batman to explain in simpler terms, and he refers to it as the League being locked in Sonic's dimension and "slipping the key under the door" so Sonic's group can unlock the way from theirs. Upon being asked by Wonder Woman if they can control where or when the Emeralds appear, Cyborg answers that he can't do so with the tech they have, which makes the former uncertain this plan will work; once again, Superman suggests for them to "put [their] faith in [their] friends", reminding them that it's the reason they sent Sonic's group to their world to begin with.
Later, a machine has been built to send the six Chaos Emeralds to the League's dimension, which Cyborg activates, shooting multicolored beams of light into the sky. Superman notes that Darkseid's elite are still a problem to the people of Sonic's Earth, as are its native threats, so they'll certainly be busy in the meantime. Meanwhile, Batman is interested in the loop-de-loop highway Flash mentioned and is asking him about it, to which Flash excitedly confirms that it genuinely exists, causing the usually serious-minded Batman to declare that he'll start his next patrol in Empire City. Green Lantern, however, is still focused on the idea of protecting Sonic's Earth, saying that despite their efforts, the planet is still "living on borrowed time", then asking Cyborg when they can estimate the Emeralds to arrive; the latter insists that beyond the anomaly, space-time rules no longer exist, but as he begins to say that he could try to do the math, he's cut off by a multicolored explosion. A portal has appeared, out of which Sonic and his friends, still in their costumes, come running, with Sonic cheekily asking if they were missed. As the Justice League members smile at the sooner-than-expected return of their new friends, Superman welcomes the group home, with Flash adding that it "took [them] long enough".
