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.

The exiles set out to locate Jasper -- who may still be alive

Izabela Vidovic stars as a teen under Bellamy's protection.

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

Abby & Jaha notice a signal from 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.

While Clarke and Raven make contact with the Ark, Abby is removed from the council and Jaha reveals that there are not enough drop ships for everyone on the Ark.

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

Tragedy strikes on the Ark during the Unity Day celebration.

John Murphy (guest star RICHARD HARMON) returns to camp claiming to have been held captive and tortured by the Grounders, and Clarke and Bellamy have very different opinions on how to handle his return. Octavia sneaks away to find Lincoln and returns with a serious warning for the 100. Meanwhile, a mysterious virus strikes camp forcing many to be quarantined, and Jasper pulls off a heroic move.

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.

The conflict on the ground explodes in the season finale.