A rescue mission is dispatched to Mars following a failed expedition, suspecting that the sole survivor, Colonel Edward Carruthers, may have murdered his crew. Carruthers insists that an unknown creature ambushed and killed everyone else. Skeptical of his claims, the rescue team takes Carruthers aboard their spacecraft for the return trip to Earth, intending to investigate further. Unbeknownst to them, a monstrous extraterrestrial has stowed away on their ship. As the journey begins, mysterious incidents and disappearances spark fear and tension among the crew, leading them to realize that something deadly lurks within the vessel.

Amidst rising panic, the crew finds themselves in a dire battle against the stowaway creature, driven by instinctual hunger. Their efforts to stop it are complicated by limited resources and the confines of space. The close quarters of the ship make evading the creature nearly impossible while forcing the team to work together despite initial distrust and fear. With every failed attempt to subdue or kill the monster, their predicament becomes more desperate. The crew must strategize creatively to survive--balancing their dwindling hope with determination to return to Earth safely. As danger escalates, friendships are tested, alliances form out of necessity, and the mission’s true nature is revealed through intense confrontations and perilous attempts at survival.