Coran's Son Runs Amuck - S1.E49

Garrett betrays the Voltron Force, allowing Lotor to fly an enormous Pulsar Cannon within range of the castle. Voltron rushes to stop it, but is attacked by a Robeast. As the two giants grapple, Lotor mercilessly blasts them both! Voltron is split into five parts, each one crashing down to Arus. If the Voltron Force can't get back together by sunrise, the Pulsar Cannon will recharge and vaporize the castle!