Opening twenty-four episodes of Gerry Anderson's live action sci-fi series. In 'Breakaway', Commander John Koenig (Martin Landau) arrives on Moonbase Alpha shortly before a nuclear explosion sends it hurtling into space. 'Matter of Life and Death' sees Dr Helena Russell (Barbara Bain) reunited with her long-lost husband Tony when he arrives at the base with a dire warning for the Alphans. In 'Black Sun', Koenig turns to Professor Bergman's new force field when the base is drawn magnetically towards a black sun. 'Ring Around the Moon' sees the Alphans trapped in an energy ring by the alien Tritons. In 'Earthbound', alien visitor Zantor (Christopher Lee) arrives on the moonbase and offers to take one person back to Earth on his ship. 'Another Time, Another Place' sees Regina haunted by visions of duplicate Alphans after the base passes through a chasm in space-time. In 'Missing Link', Koenig travels through time and space to the planet Zenno, where he finds romance with the alien Zana. 'Guardian of Piri' sees the Alphans swayed by the offer of a paradisical existence on the planet Piri, but Koenig remains suspicious... In 'Force of Life', technician Anton Zoref (Ian McShane) becomes obsessed with heat after being taken over by an alien force, and everything he touches freezes instantaneously. 'Alpha Child' sees the first baby born on Alpha growing at a vastly accelerated rate. In 'The Last Sunset', the Alphans discover a planet suitable for colonisation, but an alien force interferes with their plans. 'Voyager's Return' sees the return of the Voyager One probe, now polluting the cosmos with deadly 'fast neutrons' from its faulty drive system. In 'Collision Course', Bergman seeks to alter the Moonbase's course through space when he realizes that they are due to collide with the planet Astheria. 'Death's Other Dominion' sees the Alphans invited to share 'immortal life' on the ice planet of Ultima Thule. In 'The Full Circle', two Eagle crews find themselves transported back to the Stone Age. 'End of Eternity' sees Koenig forced to take on an immortal psychopathic killer whom he accidentally frees from imprisonment while investigating a passing asteroid. In 'War Games', Moonbase seems to be under attack when it is approached by a fleet of Mark 9 Hawk Warships. 'The Last Enemy' sees Koenig forced to act as mediator when the Moonbase becomes caught up in an interplanetary war. In 'The Troubled Spirit', botanist Dan Mateo collapses after attempting to communicate with his plants telepathically. 'Space Brain' sees the Moonbase threatened by a strange space organism which destroys an investigating Eagle. In 'The Infernal Machine', a living machine arrives on Moonbase and demands that Koenig take the place of its ageing human 'companion'. 'Mission of the Darians' sees the Alphans making contact with the cannibalistic inhabitants of a planet which has been travelling through space for 900 years. In 'Dragon's Domain', astronaut Tony Cellini runs amok and steals an Eagle after years of mental instability. 'Testament of Arkadia' sees the Moonbase rendered uninhabitable after it stops dead in space and suffers a sudden power loss.