Earth, the distant future. Beaming down from the Nerva Beacon, the Doctor and his friends discover Earth is habitable once more. Unfortunately a Sontaran officer is conducting tests on a group of human colonists to determine their ability to withstand a full-scale invasion...
| Name | Type | Role | |
|---|---|---|---|
| Dave Martin, Bob Baker | Writer | ||
| Brian Ellis | Guest Star | ||
| Donald Douglas | Guest Star | ||
| Glyn Jones | Guest Star | ||
| Peter Walshe | Guest Star | ||
| Peter Rutherford | Guest Star | ||
| Rodney Bennett | Director |