In the comics that came after the show(spoilers)
so Grace develops a computer virus that can destroy the nanites if uploaded she dies but before she dies she gives the virus to Rachel
Rachel was working on one of the pendents which according to her acts like a bug sprey for the nanites
its been 4 years since the events of the show and Rachel hasn't talked to her daughter or miles or Monroe
Rachel tracks down miles and asks miles and Monroe to help her defeat the nanines but they refuse until charlie says she is going so they agree
they fight there way to the nanites home town where everyone is connected to the nanites in a social hive kind of like the Matrix
everyone is with out independent emotions and everyone easily forgives
tom nevil is there and so is connor
Aaron and his wife are with them as well
they try to upload the virus using a laptop but Aaron and his wife get shot and killed
Tom tries to convince them to go to there side
so monroe shoots him in the head
all hope appears lost in that they are surrounded by a bunch of nanite zombie people
so rachel tells Charlie she loves her and then tells miles she loves him and to "TAKE CARE OF OUR DAUGHTER"
confirming that miles is charlie's father
she throws the pendant on the ground and says she is willing and walks out and lets the nanites in
now in her head charlie and danny are little and ben is there she says that its not real they are not her children and ben is not her husband they are the nanites
the ninites say
why are you resisting us you let us in
and rachel says Nope you let me in
and then says you called me the genius in the family you are right
i memorized the virus that will kill you
and says the connection the nanites give to humans goes both ways and she begins accessing the nanites neural net and begins to upload the virus directly from her brain
the nanites and everyone connected to the nanites drop dead including rachel
connor included
it ends with
Charlie miles and monroe riding off into the wild
with charlie and miles never seeing monroe again
(monroe was changed by his sons death and charlie says last she heard was he went to south america looking for a new war to fight and that she hopes he never finds it)
it ends with charlie saying that the power never comes back on and that maybe one day it will
the entire story is her narration to her little brother(miles son with some women he met after rachel died)
now
i have a single comment about the comics
charlie says no one knows why the power didn't come back on
its obvious the nanites did not simply upkeep the power plants and what not they absorbed electricity and when the pendants were turned on it manipulated them to release energy
with the nanites dead there is nothing to turn any power on so its obvious in order for them to get power they have to rebuild power stations
get them working etc etc