Clarke comes back as Josephine but alerts her people that she is still alive. She plans with them how to bring in the Children of Gabriel and defeat Russell.
Throughout this he is still makes nightblood possible from Madi's bone marrow, but Abby volunteers to do it and injects herself so her marrow would be taken. It doesn't work out though when Russell has all the hosts he needs but one, killing Abby so that she can become Simone's new host.
Meanwhile, Murphy and Emori go through their Naming Day and have mind drives now.
Gabriel sneaks in to try to stop the ceremony, setting up the toxin and allowing himself to get caught by Russell. Gabriel gains the upperhand but can't seem to kill him, meaning he is left behind in Sanctum as a prisoner.
Meanwhile Bellamy forces Priya to reveal the truth about Primes so Russell sets off his own toxin bomb and escapes with Clarke, Abby who is now Simone, Madi, Raven, and Gaia into space to wait out the effects.
He assumes his people will kill the other sky people down there in their rage.
When they get to space, Indra and her army are waiting for them in a stand off.