The worlds of the Justice League and Sonic the Hedgehog have become linked! Pulling the strings is the sinister Legion of Doom with the help of their newest member: Dr. Eggman! The pit of vipers is full of treachery and deceit, but they’re even more dangerous when they set their sights on the Justice League and the Sonic Heroes! Will the villains succeed in taking out the heroes in one fell swoop!? Will both worlds fall to the Legion of Doom?!