Casey and the Turtles are practising their hide-and-seek skills at an abandoned warehouse complex. All the while, a strangely familiar figure watches them from the shadows - with an army of rats at his command!

On Halloween night, a mustachioed man visits April, expressing interest in a rather unusual item: a hideous six-armed idol. But the statue is no ordinary junkshop knickknack; it can be used to invoke a horde of imps that proceed to clean out the city and bring its spoils to their master, a criminal who calls himself The King of Thieves.