The Doctor and his companions answer a distress call from a vast spaceship carrying the remnants of a dying race...
- Ships entering the exosphere are subject to gravitational pull.
- Communications arrays can be used to broadcast message, such as requests for assistance.
- Egrabill is unable to discern Susan's gender.
- Kinneret is the homeworld of the Metraxi.
- The Metraxi became sterile and so used cloning to reproduce. However, this resulted in the loss of key genetic information, shorting their lifespans with each generation.
- The Metraxi are led by Rode, a Provost.
- The ship's propulsion generator failed and radiation is leaking from the fission reactor.
- The Doctor says he is "well versed in a number of propulsion system" and notes Ian is a "scientist of sorts".
- The Doctor and his companions don radiation suits to inspect the fission reactor.
- The Metraxi have their own Bible.
- The radiation mutates Greneva so that she can have children again. She becomes pregnant as a result and the Doctor suggest many Metraxi will have been similarly altered.
to be added
- Ian recalls his own experience of radiation poisoning. (TV: The Daleks)
- The ship in need of repairs before gravity pulls it into a planet mimics TV: 42 where the ship was pulled towards a star.