“We are Grounders: Part 1” is episode twelve of season one of The 100.
Thanks to Sydney’s theft of the Exodus ship in “Unity Day”, in 51 hours the Ark will become uninhabitable. Presumably, there is no way of getting any other dropships to work.
In the previous episode, “The Calm”, Clarke and Finn had been captured by the Grounders, and Finn had been sentenced to death. Monty had discovered something unknown, possibly connected to the crash of the Exodus ship, and then vanished. It seems the Grounders are also rather more organised than thought – in a military fashion. It turns out Finn isn’t actually dead, but had been rescued by the Grounder they captured earlier, Lincoln. There’s mention of something called Reapers, which are probably a threat to both parties.
Murphy is still on a vengeance kick after the events of “Murphy’s Law”. They probably should have killed him, as he takes control of the dropship.
Things are coming to a head, but there is still a lot left unexplained. The story continues in “Part 2”.