Tako njih stotinu biva poslato na zemlju. Kapsula sleće na zemlju, ne baš nježno, ali velika većina preživi. Ostavljeni su sami sebi, a jedino su dobili upute da odu do Mount Weathera, stare vojne stanice. Tu bi trebali naći potrepštine za život, kao i radio vezu da se jave Arci. Međutim kapsula je pala dalje nego što je trebalo. Stotina otkriva da je Zemlja naseljiva, priroda buja, nema visoke radijacije, ima vode za piće i raznih izvora hrane. Međutim, to nije sve čega ima na Zemlji. Na nimalo lijep način, naučiće da na Zemlji ima još preživjelih ljudi. Prvo tu su Graundersi, plemenski organizovani ratnici, sa primitivnim oružjem. Onda tu su i Riperi, krvoločni kanibali, i Planinski ljudi, koji gle čuda, žive u Mount Weather, ali o njima nema nikakvih saznanja osim toga.

Nakon što je Jasper napadnut, Clarke, Bellamy, Finn, Wells i Murphy odlaze u potragu za njim u nadi da je još živ.Na Arci se trude da saznaju jeli zemlja još nastanjiva, Abi naređuje mehaničarima da provjere i poprave kapsule koje služe za bijeg.

Uvjeti na zemlji su i dobri i loši, otrovna magla se približava mjestu gdje je Clarcke zajedno sa Finom i Welsom koji traže ljekovite biljke za Jasperove rane.Belami odlazi sa nekoliko ljudi da potraže hranu.

Raven uspjeva pokrenuti kapsulu za bijeg i ostaje jedva živa nakon rušenja na zemlju.Abi otkriva svima na Arci planove o reduciranju populacije i slanju 100 na zemlju.

Bellamy, Finn and Jasper head into Grounder territory to search for Octavia, as flashbacks show the siblings' difficult childhood on the Ark. Meanwhile, Raven finds out about Clarke and Finn.

While Bellamy tortures the Grounder, Raven and Clarke make contact with the Ark and ask Abby to help them save Finn. On the Ark, Kane deals with his guilt, and Jaha surprises the council with a shocking revelation.

Shumway secretly orders one of the 100 to kill Bellamy. Meanwhile, hallucinogenic nuts provide Octavia with an opportunity to help the Grounder escape the camp, and Bellamy and Clarke investigate a nearby underground depot, where they find military weapons.

Finn arranges a meeting with Clarke and the leader of the Grounders in order to bring peace, however a sceptical Clarke warns Bellamy, who along with Jasper and Raven follow them to the meeting with weapons. On the Ark, Diana takes over the exodus ship.

Murphy returns to the camp carrying a horrific virus created by the Grounders to weaken the camp. After learning the Grounders plan to attack the next day, Bellamy, Finn and Raven come up with a plan to delay them.

Clarke and Finn are captured by Anya, who forces them to save the life of a victim of the explosion. Meanwhile, Raven deals with her split from Finn, and Kane fights to save the Ark and it's survivors.

Clarke and Finn come face to face with a new enemy after Lincoln rescues them from Anya, while Bellamy, Raven, Octavia and Jasper deal with a vengeful Murphy. On the Ark, Jaha makes a plan to try and get to Earth.

As the remaining members of the 100 face off against the Grounders, Jaha makes a noble sacrifice to ensure the Ark makes it to Earth.