The Alterrans

Many years after the universe has been saved by Voltron, the Garrison has become a peace foundation for planets all over. Earth is a hun for all species, and acts as a meeting place for diplomacy. When the lions of Voltron return to earth suddenly however, the paladins find themselves wondering if this peace will last. Taking their kids along, they return to the garrison ready for takeoff.
But...
It seems like the universe will need a new set of defenders.