While Sonic and crew was teleported to DC's Earth, becoming the "replacement Justice League", and just found out that their home did not disappeared thanks to the Chaos Emeralds, back in Sonic's world, Cyborg managed to create a wormhole for the JL to escape the overloaded time and space flux distortion. The League stayed on Sonic's world as Batman and Superman stated that the Dimensional Engine destabilized the planet and the Ragna Rock taking the aftermath of the effects. To get back to their Earth, they decided to find the remaining Chaos Emeralds (wait... I thought they were in DC's Earth with Sonic and crew).
So we jumped to Blaze the Cat at the Water Palace Zone from Sonic Rush, battling not only Darkseid's minions but also The Female Furies, Stompa and Mad Harriet, and defending the purple emerald. Diana came in to save the day and securing the emerald. Both her and Blaze rejoined the battle as the latter see the honor and valor within Wonder Woman.
In Westopolis and Central City highways (Sonic Adventure 2 and Shadow the Hedgehog), Metal Sonic is being chased by... Batman! And it was one-sided as Bruce was able to defeat Metal Sonic and retrieving the white emerald. (Okay, seriously Batman and Shadow had been instantly winning against their foes here).
In Lost Hex (Lava Mountain Castle from Sonic Lost World), The Flash is up against the Deadly Six (oh boy... we just have to use them again), summoned by Baron Vermin who has the yellow emerald. Flash instantly took away BOTH the emerald and the cronch (can't spell at the moment). Zavok wants to challenge the Flash but was ignored as the former was gone, remarked that he acted like Sonic. While the Flash is heading to Empire City (Sonic Unleashed) as he heard about the eight lane highway loop-de-loop, Eggman is on his Egg Fleet (Sonic Heroes), beginning his conquest to take over Sonic's world, until Superman shows up. Of course, Eggman managed to say the iconic phrase: "Is it a bird, a plane? It's Superman!" Eggman tried... yeah, tried to battled Superman in Egg Emperor, in which Clark easily destroyed. Clark asked where's the Chaos Emerald, in which Eggman stated in the Reactor Room. As Superman went downwards, Eggman screamed, "I hate that Kryptonian!"
In Luminous Jungle, Mystic Forest (Sonic Forces), the Wisps are protecting the Green Emerald from Granny Goodness. Jon Stewart stepped in to protect the Wisps. When being blasted, the Wisps charged up Jon's ring powers to give him a significant boost. After the battle, the Wisps handed the emerald to Jon, who used the emerald to charge his ring.
Back at Tails' Lab (in the Mystic Ruins from Sonic Adventure), Cyborg found a way to deal with their situation. In more simple explanation from Bruce: they're locked in Sonic's dimension, they're slipping the key (the emeralds) under the door, so Sonic and the others unlock the way from DC's Earth.
Soon, Cyborg developed a device outside the lab which created the dimension gate and soon Sonic and the others came back to their world, which we heading towards the final issue.
...oh and Flash was talking to Batman about the loop-de-loop while this happening. Bruce stated he will start his next patrol in Empire City!
