Trollhunters Season 1 Episode 43 Voltron Frees the Slaves

Lotor enslaves a peaceful planet, and forces the locals to build a gravity trap for Voltron. The local adults are quick to give in, but their kids are not. They use their knowledge of the area to set a trap for Lotor, but when their captured they become part of the trap for Voltron! Voltron and the team are forced to fight a new military-grade Robeast while rescuing the kids, and with all their automatic systems disrupted by the gravity wave!