"4,722 Hours" is the fifth episode of the third season of ABC's Agents of S.H.I.E.L.D. and the forty-ninth episode of the series overall. It aired on October 27, 2015. It was written by Craig Titley and directed by Jesse Bochco.
S.H.I.E.L.D. agent Jemma Simmons is sucked into an alien monolith she is studying, and is teleported to night-time on a barren, desert planet. She braves a sandstorm, and finds some water and a plant-like creature to eat. After 752 hours, Simmons is trapped by a man, who eventually introduces himself as Will, an astronaut sent through the portal by NASA in 2001 who has been stranded alone, and believes the planet, or an entity controlling the planet, to be evil. Will and his team had come on a year long mission of exploration, but the others had soon succumbed to the effects of "it"; two had killed themselves, while Will killed the other when the latter attacked him. Will only survived the next 14 years by hiding from "it", and luck.
Simmons uses Will's equipment, including maps he and his team made of the surrounding areas, to try and find a way back through the portal. While out scavenging for food, Simmons sees a metallic reflection in the distance, and follows it to find an old sword and some 19th century astronomy equipment. Realizing that she has entered what Will calls the "No Fly Zone", the area where his fellow astronauts all went before they died, Simmons is soon caught up in another sandstorm—this time, she sees a cloaked figure approaching her and flees back to the cave. Inspired by the astronomy equipment to use the stars and moons, Simmons deduces that the portal's location is fixed but appears to move due to the planet's rotation. By using Will's old NASA equipment and her S.H.I.E.L.D.-issued cell phone she predicts the portal's next opening, but they arrive at the location to find that "it" has apparently altered the landscape to create an impassable canyon between them and the portal. Simmons loses hope of ever returning to Earth as the portal opens and closes in front of them, and resigns herself to life on the planet with Will. The two grow close as time continues to pass.
At 4,722 hours since Simmons' arrival they see a flare in the distance. Running to it, Simmons finds her S.H.I.E.L.D. partner Fitz. As "it" arrives, Will stays behind to hold it off while Simmons reluctantly escapes with Fitz. Simmons tells Fitz of her ordeal, and he promises to help her return to the planet and save Will.
- This episode scored 3.81 million viewers upon its initial airing.