When two belligerent Dominators and their robotic servant Quarks land on the peaceful planet Dulkis planning to drop a radioactive seed into the planet's core to refuel their spaceship, the Second Doctor, Jamie and Zoe must attempt to inspire the pacifist Dulcians to resist.
| Directing | Morris Barry | Director |
| Writing | Henry Lincoln | Writer |
| Writing | Mervyn Haisman | Writer |
| Production | Peter Bryant | Producer |
| Writing | Derrick Sherwin | Script Editor |
