A spacecraft carrying an assortment of passengers including Riddick (Vin Diesel), a dangerous, shackled murderer between prisons, is forced to make a crash landing on a barren, triple-sunned planet after the craft suffers severe damage during a meteor shower. The ship is ripped into pieces, killing several crew members and leaving meek officer Fry (Radha Mitchell) in charge of the survivors. After two unfortunate deaths, the survivors discover that the only visible life form on the planet is a species of light-fearing, carnivorous, occasionally cannibalistic aliens dwelling in caverns beneath the desert surface. Using a model of the planet and its suns in an abandoned research station, Fry deduces that she and her fellow travellers have unfortunately descended on the planet on the day of its first total eclipse in 22 years, giving them mere hours before they are bathed in total darkness. Only then is it safe for the hungry subterranean creatures to emerge, seeking to feed on the remaining survivors. However, the dangerous Riddick, through black market injections received in lock-up, is able to see in darkness- causing the surviving crew members to reluctantly remain dependent on the potentially harmful criminal. As the survivors are killed one by one by the hungry creatures, they realize that Riddick may be their only hope.