THE FAN-FAVORITE CROSSOVER RETURNS! The worlds of DC Comics' Justice League and SEGA's Sonic the Hedgehog collide once more in another thrilling crossover filled with action, adventure, laughs, and perils! Mysterious mechanical rings have appeared on both worlds, linking them together and leading to all things wonderful, worrisome, and weird! The heroes are happily reunited, but little do they suspect there's a sinister origin to their reunions.