Erinn Ruth

Polaris learns more about her past; Mutant HQ comes under attack.

Dr. Campbell attends an anti-mutant summit, attempting to take the Hound program national; some of the team at Mutant HQ goes on a dangerous mission to stop him.

Thunderbird contacts a mutant lawyer to help him find the Inner Circle; Lauren and Andy have a shared dream, which distracts Andy from his training; Reed must keep a huge secret from the group; Jace picks up the mutants' trail again.

After a tip reveals there's a mole within the FBI's New York office, the team must hunt for the operative while facing extreme scrutiny from Inspector Fischer (guest star John Hodgman). The team's deepest secrets threaten to be exposed, and everyone is a potential suspect — but some, especially Jane, have more to hide.

The remaining team tries to solve a case.

With the surviving members of the team captured and held in FBI custody, Madeline and Ivy are in the final stages of their plan, but a few unlikely allies come out from the woodwork trying to stop her before it's too late.