Whilst he is exploring an asteroid Koenig is taken over by an alien race known as the Kalthon, who replace him with an exact double. In consequence every action ordered by the fake Koenig ... See full summary »



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Episode complete credited cast:
Tony Verdeschi
Alan Carter
Sandra Benes
Dr. Ben Vincent
Martha Nairn ...
Female Operative
James Leith ...
Albin Pahernik ...


Whilst he is exploring an asteroid Koenig is taken over by an alien race known as the Kalthon, who replace him with an exact double. In consequence every action ordered by the fake Koenig is solely for the benefit of the Kalthon and to the detriment of the welfare of the Alphans. Helena realizes that something is wrong when 'Koenig' is cold to the touch and needs to convince the other crew members. Written by don @ minifie-1

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Release Date:

11 November 1976 (UK)  »

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Technical Specs


Sound Mix:


Aspect Ratio:

1.33 : 1
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Did You Know?


This episode makes the final use of the cave set, originally seen on "The Metamorph". It was also used on "The Exiles", "Journey To Where", "One Moment of Humanity", "All That Glisters", "New Adam, New Eve", "The Mark of Archanon", "The AB Chrysalis", and "Catacombs of the Moon". See more »


When the duplicate Koenig returns from the asteroid and addresses the whole base, he stares straight ahead the whole time; he is reading his lines from cue cards off-screen. See more »

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User Reviews

Seed of Destruction had promise
12 September 2011 | by (United States) – See all my reviews

I love it ..and yes they did not take advantage of the evil John ..which Mr Landau played very well.. I wanted to see more ..maybe the evil John try to be physical with Helena sexually ..the torment of the real John as he was force to watch...or had the evil reflection took over John's body and alpha can't destroy the alien without killing John and doing the almost violent sexual encounter with Helena or even Maya but the encounter was stopped because the real John is fighting to get free from the alien's hold and only John and his love for Helena and vs versa causes the Alien to let loose John and be defeated ...I mean they had everything to make this episode explosive ..as for bloopers if you can call it a Blooper.. But what a blooper it was when the camera showed the evil John image coming out of the mirror.. well um that old adage still stands when a woman is so close to a man and says..is that a your hand in your pocket or your just happy to see me ?..so if you look back at that clip , when the reflection of john came out of the mirror and um he was packing more than a laser and his carrying case his um package was VERY visible .. the camera showed how very well endowed our commander was thanks to those tight skin tight pants they wore ..that was my best part of the entire episode...no it wasn't, but it got me looking closely on every episode and some episodes not just John packages are noticeable but not as clear as John's is in the clip... .. I liked the episode ..but they could have done so much it should had been a 2 part episode.they even could have had the evil john slowly take what makes John human as long as the evil John was still on Alpha..lots of possibilities that wasn't explored..Another blooper as itt were when the Alien mirror was finally called out and the real John put the sonar on to break the mirror alien why did it look like it was a shattering flat mirror instead of the mirror John start cracking like glass and it breaks apart instead of it shattering like a regular mirror when the evil john was a 3 -d image of John and he should have broken into pieces from the form it took..not make it look like it was a flat screen mirror that shattered..I guess special effects was not that advance in the 70's

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