The Phantom Ruby wasn't destroyed, and it opened several portals to dimensions, which are the Sol Dimension, Mania Dimension and Avalice. The Phantom Ruby made contact with the Chaos Emeralds, the Sol Emeralds and the Kingdom Stone, and created a powerful creature which wasn't seen before. Modern Sonic has to team up with his old friends, Classic Sonic, Blaze and a new friend, Lilac to stop the creature, and destroy the Phantom Ruby once and for all.
