SOLVED. YA Mystery/ Thriller/ Action. Female MC's brother is in a coma from doing undercover work (bombing) for this movement. Female Mc name is Charlotte (Charlie). She's trained in combat. Read around 2018-2020. Spoilers ahead. [s]

[Kris]

Ashton, is this book for teens or adults? How old are the main characters?

What's the setting (e.g., contemporary or future Earth, fantasy world)?

I added a few details to the header/ topic title. Feel free to edit it.

[M]

Bits of your description make me think of John Le Carre's book, Little Drummer Girl - the main character is Charlie, who is drawn into infiltrating a group.

[Juels]

In a Split Second by Sophie McKenzie?

[Juels]

You're welcome.