Defenders of the Earth - Season 1 - Eps 24: Doorways into Darkness
Deep in Africa Ming locates an anti-energy source enabling him to open the Nightgiant Doorway and unleash 7-story tall nightgiants to destroy the earth. Flash flies out to space to destroy a Ming satellite, but his ship is immoblized by the Merciless One's roboships, while the Phantom goes to Africa to terminate Ming's activities in the Forgotten City. As the nightgiants terrorize various parts of the globe Rick intercepts a transmission from Ming to Garax and discovers that a transport invertor will eliminate the monsters. Mandrake, Lothar, Rick, L.J., Jedda, Kshin and Zuffy take on two nightgiants outside of Central City while racing to the stadium to retrieve the saving invertordevice. As they recover the device, Rick is captured by one of the creatures. Jedda departs for Africa, where her father will use the transport invertor to close the nightgiant doorway, while the other Defenders save Rick. Out in space Flash finally fights off all of Ming's minions and blows the satellite. Jedda delivers the transport invertor to the Phantom and they battle Ming's troops before employing the device and sending the nightgiants back to their own world.
About Defenders of the Earth

Title: Defenders of the Earth
First Air Date: 1986-09-08
Last Air Date: 1986-12-05
Status: Ended
Rating: 7.518/10 (from 85 votes)
Language: EN
Seasons: 2
Total Episodes: 65
Network: Syndication
Genres: Animation, Action & Adventure
Production Companies: Marvel Productions, King Features Syndicate
Synopsis
Defenders of the Earth is an American animated television series produced in 1986, featuring characters from three comic strips distributed by King Features Syndicate—Flash Gordon, The Phantom, and Mandrake the Magician—opposing Ming the Merciless in the year 2015. Supporting characters include their children Rick Gordon, Jedda Walker, Kshin, Mandrake's assistant Lothar, and Lothar's son L.J. The show lasted for 65 episodes; there was also a short-lived comic book series published by Star Comics, created by Gerry Conway, Ross Andru and John Romita, Sr.. The closing credits credit Rob Walsh and Tony Pastor for the main title music, and Stan Lee for the lyrics. The series was later shown in reruns on the Sci Fi Channel as part of Sci Fi Cartoon Quest.
Cast

Lou Richards
Flash Gordon (voice)

Peter Mark Richman
The Phantom / Kit Walker / 26th Phantom (voice)

Peter Renaday
Mandrake the Magician (voice)

Buster Jones
Lothar (voice)

Ron Feinberg
Ming the Merciless/Warlock (voice)

Loren Lester
Rick Gordon / Young Kurt (voice)

Sarah Partridge
Jedda Walker (voice)

Dion Williams
L.J. (voice)

Adam Carl
Kshin / Young Kit (voice)

Diane Pershing
Dynak X / Dale Arden (voice)