Season One of The 100 sees the human race return, after a 97-year exile in space, to a wildly transformed Earth . . . only to discover that the human race never truly left. Clarke finds herself forced to lead a band of disposable juvenile delinquents as they face death at every turn from a world transformed by radiation, the fierce Grounders who somehow managed to survive in it and, perhaps worst of all, from themselves. Though Clarke is alternately challenged and supported by rival leader Bellamy, the two find a common purpose: survival. Through it all, Finn is helplessly drawn to Clarke, destroying his long-standing relationship with the brilliant young mechanic, Raven. And Octavia grows close to a possible enemy Grounder, Lincoln – some say too close. Meanwhile, as the 100 fight for their lives on the ground, the Ark’s situation is no better. Though Abby believes that the 100 are still alive, she does not have proof and cannot stop Kane's population reduction. The killing of 320 volunteers and the subsequent realization that the sacrifice was unnecessary breaks Kane and inflames a revolution on the Ark that Jaha, despite his best efforts, is powerless to stop. Both on the ground and in space, the final episodes reveal the true desperation of their plight as our heroes risk everything just to stay alive. Noble sacrifices and heartbreaking choices change everyone forever and leave them scattered to the wind at the season’s end. 
Set in the distant future, 97 years after a nuclear war has devastated the surface of Earth, the only remaining humans are residents of a flotilla of orbiting space stations known as “The Ark”. 100 juveniles convicted of various crimes are sent to the surface to test its habitability. Among them is 17-year-old Clarke Griffin, the daughter of the Ark's chief medical officer and chief engineer. As the 100 explore, back on the Ark the leader of the Ark, Chancellor Jaha, has been shot, causing Councilman Kane, the second in command, to take charge.
March 26, 2014
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 to repair a broken 130-year-old Russian Mir-3 escape pod.
April 2, 2014
Elizabeth Craft & Sarah Fain
In a desperate attempt to treat Jasper’s festering wounds, Clarke, Finn and Wells set out in search of a seaweed antibiotic. Bellamy (Bob Morley) and his crew go hunting for food, and are joined by Charlotte (guest star Izabela Vidovic), a lovable 13-year-old who feels safe under Bellamy’s protection. A thick, acidic fog appears, forcing Clarke, Finn and Wells to seek shelter inside an ancient van. While they are trapped, Clarke confronts Wells about his betrayal that resulted in her father’s death.
April 9, 2014
P. J. Pesce
T. J. Brady & Rasheed Newson
After the shocking death of one of their own, Clarke and Finn grow closer as they try to figure out a way to communicate with the Ark. Bellamy must keep the group from turning on one another as life on Earth takes a desperate turn. Meanwhile, Abby risks having herself floated in order to give Raven the chance to stow-away in the escape pod bound for Earth.
"Twilight's Last Gleaming"
April 16, 2014
Clarke's newfound romance with Finn is threatened. Octavia suffers a blow to the head and wakes up to find a Grounder watching her. On the Ark, Abby exposes Kane's plan to reduce the population of the Ark. Jaha and Abby notice a signal and realize at least some of the 100 must still be alive on Earth.
"His Sister's Keeper"
April 23, 2014
Tracy Bellomo & Dorothy Fortenberry
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 childhood on the Ark.
"Contents Under Pressure"
April 30, 2014
Akela Cooper & Kira Snyder
Clarke and Raven make contact with the Ark, and Abby guides Clarke through a dangerous procedure in a desperate move to save one of their own. Meanwhile, on the Ark, Abby is removed from the council and former Chancellor Diana Sydney takes her place. Jaha reveals to Abby that there are not enough drop ships for everyone on the Ark to go down to Earth and Kane begins to deal with his guilt over his recent decision.
May 7, 2014
Story by: Andrei Haq Teleplay by: Elizabeth Craft & Sarah Fain
Clarke and Bellamy go on a mission to find supplies for approaching winter. Some of The 100 accidentally eat nuts with powerfully hallucinogenic properties and lose their grasp on reality. Meanwhile, Octavia seizes the opportunity to help a friend escape and a terrifying event brings Clarke and Bellamy closer. On the Ark, Commander Shumway secretly assigns one of the 100 to kill one of his own and the treacherous actions of Diana Sydney are revealed.
May 14, 2014
Kim Shumway & Kira Snyder
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 grow closer. Meanwhile, tragedy strikes during the Unity Day celebration on the Ark.
"I Am Become Death"
May 21, 2014
T. J. Brady & Rasheed Newson
Murphy returns to camp claiming to have been held captive and tortured by the Grounders. 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. Jasper pulls off a heroic move.
May 28, 2014
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.
"We Are Grounders (Part 1)"
June 4, 2014
Tracy Bellmo & Akela Cooper
Clarke and Finn escape one dangerous situation only to find themselves faced with a new enemy. Bellamy makes a heroic move to save Jasper. Raven faces a new danger and Murphy finally gets his revenge. Meanwhile, those remaining on the Ark are coming to terms with the inevitable.
"We Are Grounders (Part 2)"
June 11, 2014
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.
The 100 - Season One Trailer
Season One was originally supposed to air in January but was moved to March.
The CW moved The 100 and had it take over The Tomorrow People's time slot.
The 100 was renewed for a second season in early May.
The Special and Visual Effects Team for the episode We Are Grounders (Part 2) was nominated for an Emmy Award on July 10th, 2014. 
After the finale, there were 54 Delinquents remaining.
46 of the Delinquents died during Season One
In the show, this season started on September 13, 2149. It ended on October 11, 2149.
The events that occurred in this season took place over 29 days.
Season One can be bought on DVD on September 23, 2014.
Season One will be available on Netflix on October 22,2014.