With the antidote to the plague found, the Silurians retaliate and take over the research centre. They now intend to destroy the Van Allen Belt, resulting in death for all mankind.
| Name | Type | Role | |
|---|---|---|---|
| Malcolm Hulke | Writer | ||
| John Churchill | Guest Star | ||
| Paul Barton | Guest Star | ||
| Nigel Johns | Guest Star | ||
| Alan Mason | Guest Star | ||
| Timothy Combe | Director |