S6, E15: When Frank Prady (David Hyde Pierce) decides to go after Governor Florrick as a campaign tactic, Alicia is faced with the decision of whether or not to attack Peter's record as well. Also, when Florrick/Agos/Lockhart take on the case of a man paralyzed by a malfunctioning gun created on a 3D printer, they call on Kurt McVeigh (Gary Cole) to testify as an expert witness, which leads to a rift between Diane and her husband. Michael J. Fox and Denis O'Hare also guest star.