Voltron: Lion Force, The Buried Castle

S1 E19: An ancient castle appears from the mists on Planet Arus. Pidge and some of the local kids go exploring, but it turns out to be Haggar's trap! The rest of the Voltron Force arrives, but they are also trapped in the castle. Haggar's Robeast begins to tow the castle off to Planet Doom. The team's last hope is Keith, who manages to escape by hijacking one of Zarkon's ships. But can he defeat the forces of Doom and free the others all by himself?