From the introduction:
Skylands. A wonderous world filled with magic and adventure. An endless expanse of clouds and fantastic floating islands. At the center of the world sits the Core of Light, which keeps darkness at bay and peace within Skylands. Only when the Core of Light fails to function, darkness creeps in to engulf Skylands. In Skylands, countless minions of the darkness and the Dark Portal Master himself, Kaos, battle for control against the Skylanders, guardians of the sky world. Most of the time, Master Eon and the Skylanders are able to maintain peace, but Kaos is always looking for ways to enact his devious plans. This time, Kaos has got his hands on the Book of Dark Magic. He plans to use this powerful spell book to manipulate all existing portals, isolate Skylands and become the sole ruler. But Kaos’ plans backfire! The portals start erupting one by one, and soon create a huge space explosion, so powerful that it causes a rift between dimensions! The rift starts pulling in entities from all corners of space, including things that don’t belong… And with it, the Portal Masters from Earth are suddenly transported into Skylands!