The Catacombs Episode Guide

The AB Chrysalis

Catacombs of the Moon Year 2 - Episode 12 Seed of Destruction

Writer Tony Barwick
Director Val Guest
Guest Stars Ina Skriver,
Sarah Douglas
Original Title The Chrysalis A B C
Belgium (Flemish) Spiegelbeeld
Denmark Pupperne Chrysalis
Spain Las crisálidas A y B The chrysalis A and B
France/Canada Les chrysalides AB The Chrysalis AB
Germany Planet der Wastenden Planet Of Waiting
Italy Le crisalidi The Chrysalids
Japan Space Lightning! Shockwave
Portugal As Crisálidas A-B The Chrysalids A-B
Portugal Planeta das Crisálidas Planet of the Chrysalids

A planet on which people enter a chrysalis stage when they reach their allotted span.... Reborn, they attain new heights of mental and physical perfection...but for Moonbase Alpha, the planet threatens disaster.


  • Shooting script titled The Chrysalis A B C dated 18th May 1976. Yellow page revisions June 30th (during filming, from 18th June-6th July).
  • A "Double Up Koenig" script, filmed simultaneously with Catacombs Of The Moon
The A B Chrysalis


Int. Command Centre
Int. Medical Centre
Int. Power Room
Int. Weapons Section (screens only)
Int. Alpha Corridor
Int. Travel Tube
Int. Eagle Pilot Section
Int. Eagle Passenger Section

Int. Alien Elevator
Int. Underground Space Station
Int. Alien Tunnel
Int. Chamber
Int. Rejuvination Chamber
Int. Conversation Chamber


  • The spheres were 5ft (1.5m) tall, so big that Martin Bower couldn't get them out of his workshop door; he had to saw through the door frame.
  • The effect of the final explosion is also used in Space Warp.
  • The voice probes were fibreglass and blown by compressed air. They were filmed at 4 times normal speed (94 feet a second) and reversed, so the voice probes bounce in slow motion up to the stands. In some shots the stand wobbles before the probe reaches it. There is only one shot of the actors and probes together.
  • The alien elevator is used on Alpha in Space Warp and The Seance Spectre.
  • The DVDs contains behind-the-scenes footage taken at Bray Studios during the filming of this episode (especially the Eagle landing on the planet), with a commentary by Brian Johnson.
The A B Chrysalis
The spheres were reused as the waste domes in Bringers Of Wonder



  • Chlorine is a greenish yellow gas, a very powerful oxidising agent that is highly toxic to all life. It is like oxygen in that it burns with very exothermic reactions, so it is possible that another type of life could evolve to breathe it. Naturally it is rarely released (like oxygen), so a chlorine atmosphere must be created by an evolved biosphere (as Earth's atmosphere was). It is unlikely that lifeforms so identical to humans would evolve, so similar as to be attracted to Koenig.
  • Alan collapses and is unconscious for some time. This probably means permanent lung damage. Chlorine attacks the capillary blood vessels in the lungs, causing the lung tissue to inflate into a wet spongy mass through which gas exchange is not possible (a condition called pulmonary oedema); the victim suffocates to death. It was used this way in gas attacks in World War I.
  • Although some animals undergo metamorphosis from a larval to an adult form, the aliens use it to rejuvenate and have a long lifespan suggesting it is an artificial hibernation.
  • From one large circle and four smaller but identically sized circles the voice probe assumes they are from Earth. It also assumes all Earth people speak English.
  • Explosions at regular 12 hour intervals do not necessarily suggest intelligence- as the Alphans prove by slipping past the defence easily. The explosions actually draw attention to the planet.
  • Electric charges cannot travel through the vacuum of space. The effects suggest a real explosion with a slower-than-light debris shockwave.
  • Maya calculates their ETA to 2 decimal points of a second- absurd precision which takes longer to say.
  • Koenig's blast procedure leaves something to be desired- kneeling by the sharp corner of a desk covering his ears.
The A B Chrysalis
From a few circles, the aliens deduce the exact solar system the Alphans are from.

The A B Chrysalis
Blast procedure...



1288 days after leaving Earth orbit (Mon 24 Mar 2003)

Alpha Personnel:

0 fatalities.

Alpha Technology:


Eagle 1 (Koenig)

Maya transformations:

Kreno animal
The A B Chrysalis
Albin Pahernik wears the Kreno costume
The A B Chrysalis


Unnamed planet

The A B Chrysalis The A B Chrysalis


A, B, C, guardian, all humanoids

The A B Chrysalis The A B Chrysalis The A B Chrysalis The A B Chrysalis


The A B Chrysalis




See more observations


  • At the end, Helena questions Koenig about "those women on the planet. Beautiful and naked, I understand." and he claims he didn't really notice. In the script she throws her commlock at him.
The A B Chrysalis
These shots never appeared in the episode- Koenig wears his jacket throughout on screen.



Shall we dance? Fanderson sells a colour version of this publicity shot showing one of the film crew watching. Click for larger image

External Links

Contents copyright Martin Willey