One of the most devastating developments of Season 1 is the shocking revelation about Jane's best friend, Maggie Shaw (Julie White). Maggie and Jane have been friends for over 15 years, having met when Jane started working for the CIA. Maggie became Jane's mentor and eventually her close friend, and convinced her to become a spy rather than sit behind a desk. They're so close, Jane's kids think of her as their aunt.
This all comes crashing down in "Spies, Part 1" and "Spies, Part 2" when Jane finds out that Maggie has been working as a double agent for many years. Moreover, Maggie's working with a sought-after Chinese operative named Bao, who happens to be her long-lost son. Jane is devastated by the betrayal, even if she understands why Maggie did what she did.
Jane spends several episodes reckoning with this development, but the show really only touches the surface of how it must be affecting her. Jane trusted Maggie with her kids' lives. She's also someone who takes truth, duty, and loyalty extremely seriously. We imagine it will take years for Jane to truly recover from Maggie's betrayal, if she ever does, and we hope we see more of that process in Season 2.