Space: 1999

A verbal communication from the planet Ariel destroys the crew's hopes of settling on a planet apparently similar to Earth.

Koenig decides to use explosives to prevent a collision with an unseen intelligence; guests Shane Rimmer, Carla Romanelli.

A botanist's (Giancarlo Prette) experiments in communication between plants and man bring bizarre, frightening results.

Koenig must decide if the crew should evacuate to an abandoned planet or escape when Moonbase Alpha's orbit ceases.

Koenig arranges a cease-fire between two warring planets when Moonbase Alpha is caught in their fire; guest Caroline Mortimer.

Koenig and Helena appeal to the daughter of an alien ruler planning to use the Alphans as fuel for a biological computer.

Bizarre capsules circling Moonbase Alpha contain ancient killers in suspended animation; guests Peter Duncan, Stacy Dorning.

Helena, John and Alan travel back in time to plague-infested Scotland; guests Freddie Jones, Isla Blair.

A race of superior robots forces Helena and Tony to teach it human emotions; guests Billie Whitelaw, Leigh Lawson.

A willful computer forces Helena and Koenig to accompany it to a poisonous planet; guest Bernard Cribbins.

A godlike being (Guy Rolfe) offers the Alphans a chance to live on a planet resembling Eden.