The 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. Coran and Hunk leave to acquire a new crystal, Keith and Allura rush to the Arusian village as it is being attacked by the Galra while Shiro and Pidge remain at the castle with Lance. However, Sendak attacks and overpowers Shiro before plugging a Galran crystal into the castle, the attack on the Arusian village being a distraction. However, Pidge evades capture and with Allura's guidance is able to sabotage the Galra's efforts to launch the Castle. Meanwhile, Hunk and Coran arrive at a nearby Balmera, a large petrified creature the size of a planet from which the Alteans acquire crystals. However, they discover that it has been taken over by the Galra and crash in the subterranean mines.