Mismatched cousins Kaz and Truly barely survived their first alien invasion. When the villainous Horde Empire returns, the space conquerors look twice as dangerous. This time, Maximo Skulldigg and the rest of the Horde have a tool to sideline the kids' mysterious protector, cosmic knight Trinn Cyclo. To make matters worse, the Horde kidnaps Kaz's parents! If Kaz and Truly hope to rescue the grown-ups, they'll need all the luck they can get. They'll even need Kaz's catlike, UFO-obsessed uncle, Lucky.