Stowaway (2021) is a compelling sci-fi thriller that delves into the ethical dilemmas of space exploration. Directed by Joe Penna, the film follows a three-person crew—commander Marina Barnett (Toni Collette), biologist David Kim (Daniel Dae Kim), and medical researcher Zoe Levenson (Anna Kendrick)—on a two-year mission to Mars. Their journey takes a drastic turn when they discover an unintended stowaway, launch engineer Michael Adams (Shamier Anderson), whose presence compromises the ship's life support systems, leaving insufficient oxygen for all four to survive.

The film excels in building claustrophobic tension and moral complexity, as the crew grapples with impossible choices in the vast emptiness of space. Performances are standout, particularly Anna Kendrick's empathetic turn and Toni Collette's authoritative yet vulnerable portrayal. While the pacing is deliberate, it effectively underscores the weight of each decision, making the scientific and emotional stakes feel authentic.

Viewers should watch Stowaway for its intelligent storytelling and realistic depiction of space survival, avoiding flashy action in favor of psychological depth. It's a thought-provoking adventure that questions sacrifice and humanity under extreme duress, perfect for fans of character-driven sci-fi like Gravity or The Martian. Stream it online for a tense, emotionally resonant experience.