On February 1, 2017, the CW aired the one-hour season premiere of its renowned sci-fi series, The 100. In the first episode of season four, titled “Echoes”, the characters begin to deal with the new issues that arose at the end of the previous season.

The 100 first aired in October of 2014 and its fan base has continuously grown ever since. The program revolves around a dystopian society and its extraordinary characters. Nuclear warfare plagues the earth and Earth’s survivors are transported into space to live aboard a ship. 97 years later, a group of 100 juvenile delinquents are sent back to Earth to obtain information about whether the planet is habitable. The Earth turns out to be habitable, but the characters from space, also known as the Sky People, discover they are not alone; the Earth has been occupied by people who call themselves Grounders. Since then, the Sky People have been struggling with conflicts involving their own members and the Grounders.

The premiere starts off with Clarke (Eliza Taylor) and Bellamy (Bob Morley) surveying the damage from defeating A.L.I.E., an artificial intelligence. Clarke has discovered that they have only six months before radiation destroys the Earth, and she is not sure how to notify the rest of the characters about their impending deaths. However, more characters find out about the nuclear apocalypse that is to come, and they begin to assess how much damage it can cause and how they may be able to stop it.

Meanwhile, the Grounders blame the Sky People for the destruction, and one Grounder sees this as an opportunity to declare war on the Sky People. Octavia (Marie Avgeropoulos) fights alongside Clarke and the other Sky People against the Grounders, Raven (Lindsey Morgan) researches about the radiation, Jasper (Devon Bostick) considers committing suicide, and Murphy (Richard Harmon) decides to run away with his girlfriend.

Every character seems to have their own problems to deal with, but the main issue is the nuclear destruction arriving in six months. Will the Sky People be able to save everyone from the radiation? Will the Sky People and Grounders develop a civil relationship in order to concoct a plan regarding the nuclear apocalypse? Tune in for the rest of the season of  CW’s The 100 on Wednesdays to find out.