In the distant future, the spaceship Hunter-Gratzner is transporting passengers in cryostasis. Among those are a Muslim preacher who goes by the title of Imam, accompanied by three young sons, traveling to New Mecca; a teenager named Jack; a pair of prospectors named Shazza and Zeke; a merchant named Paris; and a law enforcement officer, William J. Johns, who is escorting the notorious criminal Richard B. Riddick. Riddick has surgically modified eyes that allow him to see in the dark but are highly sensitive to light.
Micrometeoroids from a comet rupture the ship's hull, killing the captain and sending the ship off course. The surviving crew members attempt to land the ship on a nearby planet. As the ship falls apart, docking pilot Carolyn Fry attempts to dump the passenger section to reduce their weight but co-pilot Owens prevents her. During the crash, several passenger compartments are destroyed and Owens is fatally injured.
The group explores their surroundings, noticing that the three suns surrounding the planet keep it in perpetual daylight. They find an abandoned geological research settlement, with a water well and a dropship with drained batteries. Zeke is killed but his body is missing and Riddick is immediately suspected. While searching for Zeke's body, Fry barely escapes from photosensitive aggressive underground creatures. Johns offers Riddick a deal: if he helps them escape the planet, he'll go free.
After the group takes a power cell to the dropship, one of the young sons is ambushed and eaten inside one of the buildings, and they realize the geologists were all killed by the creatures. An orrery shows that an eclipse of the entire planet is imminent, meaning the creatures will be free to hunt above ground. Johns informs Fry that Riddick can pilot the dropship and Riddick reveals to Fry that Johns is actually a bounty hunter and a morphine addict.
The group returns to the crash site on a solar-powered sand truck to retrieve more power cells for the dropship before the eclipse, but it begins just as they get there. Creatures pour out of the ground and rip Shazza in half. After regrouping, Riddick agrees to Fry and the others to lead them back to the dropship on foot through the darkness, thanks to his special sight, and the group salvages for any sources of light they can find to scare away the creatures. The trip back to the dropship starts with the power of their light sources getting accidentally cut after Paris is killed and has them cross their tracks. After Riddick reveals to the group Jack is actually female and the scent of her blood is drawing the most attention from the creatures, Johns suggests to Riddick to use Jack as bait to keep the creatures away from the rest of the group, but Riddick engages Johns in a hand-to-hand fight, wounds him and leaves him as a distraction instead. The rest of the survivors push on, while Riddick drags the power cells behind him.
After the Imam's last child is killed and rainfall starts putting out their Molotov torches, the group, down to Riddick, Fry, Jack and Imam, finds shelter in a small cave not far from the settlement. Riddick leaves them there and takes the power cells to the dropship. Inside the cave, they discover bio-luminescent worms, which they stuff in the empty bottles to use as light. Fry leaves the cave and finds Riddick powering up the ship, ready to leave without them. She pleads with him to help her rescue the others, but he offers to take just her with him. Fry refuses and demands that Riddick join her in going back to save the Imam and Jack. Riddick agrees out of sheer fascination with this decision. They find the Imam and Jack, and while returning to the ship Riddick is separated from the group and wounded by the creatures; Fry goes back to help Riddick but is speared and carried off by a creature after attempting to save him. Riddick makes it to the ship and waits until the last possible moment before engaging the engines to incinerate as many creatures as possible. While leaving the planet, Jack asks Riddick what they should tell the authorities about him; he tells her to say that Riddick died on the planet.
