Co-written together with Dan O'Bannon, who also worked for the scenography and interpreted one of the astronauts, "Dark Star is a recovery in satirical key of Kubrick's 2001:A Space Odyssey [...] and Californian hippy style of life, but, also, an anticipation of the Sci-Fi stream in the Seventies." (P.Mereghetti, Dizionario dei Film 1996, Baldini & Castoldi, Italy).

Dan O'Bannon was later to be one of the author of the screenplay for Ridley Scott's Alien.

The crew (Talby, Boiler, Pinback and Doolittle) lives in apathy and frustration: destroying planets has become routine.
In all their travelling, they couldn't find any sign of intelligent life, apart form a beach ball shaped alien, that Pinback rescued (and now reluctantly attends) thinking it was a good idea to give the ship a mascotte.

They kill the time as they can: Boiler likes to play with a knife, hammering the blade in the table between is finger, faster and faster, without making a grimace when the knife pierce his hand and, later, tries to hit a metal plate with a laser rifle, at the risk of perforating the ship's hull.

Pinback, badly tolerated by the other companions, tries in vain to improve the crew's morale with innocent tricks (loose eyeball glasses, rubber chicken,...), but he's the first to be out of mood (we then discover that he's no astronaut at all, and got in the mission by chance, but, who cares?).

Lt. Doolittle, ship's commander after Cap.Powell's death, has apperently lost interest in the mission. Data about probability of intelligent life don't excite him, he doesn't want to name a new star discovered by Pinback ("Commander Powell would have named it!", Pinback claims), he only wants coordinates of planets to destroy.
To distract himself, he plays a strange organ in which the hammers hit bottles full of water at different levels.

Talby lives in the dome on top of the ship, gazing at celestial bodies, giving now and then the diameter approximation of the planets to be destroyed.
His greates dream is to see the legendary and mysterious Phoenix Asteroid.

The soothing and sexy female voice of the on board computer accompanies the life of the crew, notifying alerts or scheduled activities (like the feeding of the alien).
Twilight fall on NGC-891 by Martin Segundo and the Santella Strings is one of the tracks it is programmed to broadcast for the listening enjoyment of the crew.

An incontrollable series of events leads to the crisis that breaks this sick routine: the ship goes through an asteroid storm; the beach balloon alien (that Pinback tries to feed, almost remaining killed, in one of the most exhilarating scenes) cause a damage to the ship's communication circuits. One of the smart bombs used to annihilate planets, Bomb #20, convinced more than once by the ship's computer to re-enter the bomb bay, now is firmly willing to explode, mantaining to have received the order to do it from Sgt.Pinback.

Advised by Commander Powell (actually freezed in suspended animation, the brain being sustained by electrical stimulation), Doolittle starts with Bomb #20 a philosophical dialogue in a desperate attempt to avoid the explosion.