Voltron: Defender of the Universe, Vol. 4 (Tin Case)

A series of unnatural earth tremors frightens the Space mice into action. Rather than running or hiding, they begin to train like soldiers, and fight a pitched battle against the Blue Cat. To back them up, Pidge builds them their very own robot vehicle, a flying mouse. Before they have a successful flight, Voltron is trapped by a powerful underground Robeast. It's up to the Space Mice to launch a rescue mission!