A witness's death pulls Mary out of administrative leave in the second-season premiere. While working on the case, she also must cope with her post-traumatic stress disorder.

In My Humboldt Opinion: When a marijuana mastermind from the NorCal grasslands is unable to testify without the pot to neutralize his severe anxiety disorder, Mary finds herself in the weeds.

A Stand-Up Triple: When a hot mom-on-the-prowl witness is having problems with her brood, Mary soon finds herself playing babysitter to three difficult kids.

Rubble With A Cause: When a huge building collapse traps one of Mary's witnesses under the rubble and out in the open, his injury plays second to the threat of a professional assassin up on the roofs.

Aguna Matatala: An Orthodox Jewish witness, whose estranged wife refuses to enter WITSEC, soon finds himself being followed by a mysterious man (guest star Richard Schiff) who answers to a higher authority.

One Night Stan: When Stan's first witness turns up dead, with his badge amongst the bones, he becomes the chief suspect - forcing Mary & Marshall to dig deeper into a 20-year-old love triangle.

After the engineer of a collapsed bridge is targeted by the families of those who died in the accident, he enters Witsec and tries to prove he's not responsible for the collapse.

Mary and Marshall suspect that a new witness may be involved in a string of murders and the stabbing of Mary's friend. The pair try to determine if the witness is truly the killer before another victim surfaces.

Brandi is charged with murder and drug trafficking by Agt. O'Connor, leaving Mary to try to uncover the reasons behind his vendetta against her sister.