For thousands of years the Rainbow Gates have remained closed.

In Equestria:

One day, a trio of young fillies on a quest for their Cutie Marks stumble upon a gate. What they find beyond the gate is an adventure of a lifetime. Monsters, knights, strange blank flanked ponies, witches and dragons and creatures that go ‘shoo-be-doo’. Can the Crusaders find their way home? And what is the mysterious shadow lurking in the darkness…

In Dream Valley:

It is celebration time for the Ponylanders and their allies, the Flutter Ponies, the Grundles, the Stonebacks and Sea Ponies. A new ally had joined their ranks, and a witch from the Volcano of Gloom has betrayed her own. But when their friends vanish, Wind Whistler and Gusty must cross a mysterious gate to a strange world of wooden wolves, diamond loving dogs, griffins and ponies that seem both familiar and strange. And lurking in the darkness, is an old foe.

Two worlds. Two enemies. Two shadows.

Let the Rainbow between Worlds connect.