After his home kingdom is destroyed by the ancient devil priest Mumm-Ra, the young Thundercat Lord Lion-O leads a team of survivors as they fight evil on Third Earth.After his home kingdom is destroyed by the ancient devil priest Mumm-Ra, the young Thundercat Lord Lion-O leads a team of survivors as they fight evil on Third Earth.After his home kingdom is destroyed by the ancient devil priest Mumm-Ra, the young Thundercat Lord Lion-O leads a team of survivors as they fight evil on Third Earth.