The 100

In the series premiere, 100 young exiles from a dying space station are sent to the planet Earth 97 years after a nuclear apocalypse to see if it's habitable.

Having discovered that Jasper may still be alive, Clarke, Bellamy, Octavia, Finn and Monty set out on a mission to locate their friend and are shocked at what they find. Meanwhile, on the Ark, Abby is determined to get to Earth, and enlists Raven (guest star LINDSEY MORGAN) to craft an escape pod.

Clarke, Finn and Wells set out in search of an antibiotic to treat Jasper's wounds, when an acid fog forces them to seek shelter...and forgiveness for past crimes.

Bellamy tries to keep the group from turning on one another.

Clarke's newfound romance with Finn is threatened. After suffering a blow to the head, Octavia wakes up to find a Grounder watching her. On the Ark, Abby exposes Kane's plan to reduce the population of the Ark. Then Chancellor Jaha and Abby notice a signal and realize at least some of the 100 must still be alive on Earth.

Bellamy leads his crew into Grounder territory as they search for Octavia. Raven can't help but notice the deep connection between Finn and Clarke. Meanwhile, flashbacks reveal Bellamy and Octavia's difficult childhood on the Ark.

Clarke and Raven make contact with the Ark.

Clarke and Bellamy go on a mission to find winter supplies.

Clarke and Finn attempt to broker peace with the Grounders but all hell breaks loose when Bellamy, Jasper and Raven show up armed and ready for battle. Octavia and Lincoln (guest star RICKY WHITTLE) grow closer. Meanwhile, tragedy strikes during the Unity Day celebration on the Ark.

Murphy returns to the camp.

With a low food supply at camp, Clarke and Finn lead a group out to hunt for food and wind up in a compromising position. With Finn's life in danger, Clarke makes a game-changing decision. Meanwhile, Raven makes Bellamy an offer he can't refuse. On the Ark - Kane risks his life and is reunited with Chancellor Jaha and Abby.

Should they stay or should they go? Those remaining o the Ark must come to terms with the inevitable. Meanwhile, Clarke and Finn find themselves facing a new enemy.

In the first season finale, Clarke pleads with Bellamy to do the right thing as conflict on the ground comes to a head. Bellamy forces Octavia to make a difficult decision. Raven and Jasper work against time and Finn makes a bold move. Meanwhile, the situation on the Ark comes to a stunning conclusion.