Six volunteers, four scientists, an engineer and an architect, seal themselves inside a dome on the slopes of Mauna Loa for 366 days, the longest Mars simulation ever attempted in the United States. The film follows the HI-SEAS crew through NASA's isolation study, tracking how they ration water, manage food stores, and run experiments while living under the restrictions a real Mars mission would impose: no fresh air, no privacy, and a communication delay built in to mimic the lag between Earth and Mars. Interviews with the crew members chart the psychological toll of confinement inside a small volcanic habitat, from friction between housemates to the strain of not seeing the sky change for months. Mission organizers and researchers explain what NASA hopes to learn about crew dynamics before committing astronauts to years-long deep space missions. The volcanic terrain outside the dome stands in for the Martian surface throughout, and the cameras stay close on the crew's daily routines rather than dramatizing the setup, letting the slow accumulation of days do the work of showing what isolation actually costs.