Roots: Greek myth. Lord of Light. Lucie mentions Romeo and Juliet and the Beatles' "When I'm Sixty-Four". The remake of Battlestar Galactica (downloading minds into new bodies when the old bodies die).
Technobabble: The RSK machine has a positronic sump.
Dialogue Triumphs: "I am Lucy of the M62 and this is my bumbling assistant the Doctor."
"Theosophy? Ha! Surely you mean theophany? Because we're not talking about real gods here, are we? We're talking about the appearance of gods. Your heavenly powers are a little too mechanical for my liking. And, if I may be so bold, Lord Zeus, your demeanour is not very godlike."
Continuity: "Zeus" was the leader of the people who originally came to the planet a thousand years ago. He and a handful of others use RSK (Remote Synaptical Kinesis) to transfer their minds into new bodies when their current ones wear out. RSK only works if the new body is a clone of the original: if the clone isn't perfect, parts of the mind can be lost during transfer. The colonists cannot grow clones by forced acceleration and have to rear them from babies: when they transfer their minds into their bodies, the mind of the clone is wiped and permanently lost. Clones are only suitable for transfer up to a certain age: after this, they are retired and get to live out their lives. The group of colonists who undergo cloning forbade all talk of other worlds and technology, and decided to pose as the Greek Gods to maintain control of their people. They once experimented with transferring their minds simultaneously into multiple bodies. Few of the original group have survived, due to accidents too far from the RSK, mental illness, and other problems.
The Doctor claims he would donate a kidney or heart to a family member if he were stranded on a primitive planet.
Links: Lucy mentions 1974 (Horror of Glam Rock). The Doctor mentions his granddaughter.
Location: Caleva [which may be the name of the planet or a country or region on it].
Future History: RSK machines are illegal throughout most of the galaxy.
Unrecorded Adventures: The Doctor has been trying to take Lucie to Blackpool.
The Bottom Line: "He's my heir. And my spare." A simple and rather straightforward story is made special by some inspired casting and direction, and a sweet ending.