Fall of the Castle of Lions

The team and Arusians celebrate Voltron's victory in the castle, but the festivities come to a halt when Pidge reveals his intentions to leave the team and search for his missing father and brother. As the team tries to convince Pidge to stay, Haxus, one of Sendak's soldiers, is able to sneak a bomb drone into the castle, causing it to destroy the crystal that powers the entire castle and severely injure Lance in the process.