With the help of the Serpentine, Lord Garmadon forges the Mega Weapon from the Four Golden Weapons of Spinjitzu. This unspeakable power gives him new ways to try and destroy the ninja. But when he is betrayed by the Serpentine and abandoned on an island, he meets the Overlord. Garmadon learns that fate has brought him there for a destiny far greater and more sinister than even he had ever imagined.