List of Lie To Me Episodes - Series Overview - Season 2 (2009–2010)

A young woman approaches Lightman at his book signing, believing she has psychically seen a murder. Lightman finds that the woman has multiple personalities, and he believes that one of her personalities witnessed the murder. Lightman passes off helping Agent Reynolds vet a potential Supreme Court nominee, instead choosing to pursue the case of the multiple-personality woman. The case is passed on to Torres, whom the nominee does not treat with respect due to her age. Torres puts her preconceived judgments about the man aside when she analyzes the facts. Lightman unlocks the woman's original personality, who helps Lightman find the original murderer. Zoe informs Lightman that she is taking their daughter, Emily, and moving to Chicago to open a law firm. Lightman buys out her stake in The Lightman Group so that she can start her own practice in town.

Zoe enlists Lightman to help with her client—a 22 year-old star college football player who has been accused of statutory rape with a 16 year-old girl. The case hits home for Lightman, who learns that his daughter Emily was friends with the group of girls who attend these college fraternity parties. Through the course of their investigation, Lightman and Torres determine that Zoe's client was set up by the girl, whose friends leaked the video of the hookup. Lightman figures that the man did not know the girl was underage, noting that his face showed that he knew he shouldn't find underage girls attractive. Meanwhile, Foster and Loker travel to a religious compound to determine whether its claim of IRS exemption is valid. They believe the head of the compound is holding the women against their will. Foster facilitates the escape of one woman and her children, and faces the wrath of both Loker and the government. At the end, the girl's father believes the system is protecting the football player and decides that someone has to pay. He shoots the prosecutor that dropped the charges against the football player, with whose death the episode ends.

Eric Matheson (Garret Dillahunt) is determined to prove that he didn't murder his wife. Torres is assigned to investigate the murder, and goes to the house of the victim's sister. Matheson finds Torres' car and gets into it after she forgot to lock the door. When Torres returns, Matheson holds her at gunpoint, instructing her to drive to the Lightman Group offices. Cal makes a deal with Matheson, asking him to let all the employees go as long as he helps prove Matheson's innocence. Matheson complies, and Foster, Loker, Reynolds and Torres attempt to solve the case, while Reynolds has second thoughts about not calling the authorities. Cal and the team find out that Matheson was actually innocent and that his wife was actually killed by a loan shark. Matheson demands to see the loan shark, saying he will either take his life or Cal's. Cal pleads for Matheson to kill him, but Foster, Loker and Reynolds trick Matheson into letting his guard down after a disguised Loker pretends to recount the last moments of Matheson's wife's life. As Matheson takes aim on Loker, Reynolds draws his gun and shoots Matheson, disarming him. The episode ends with Lightman at Foster's home, asking if he could sleep in her spare room for the night.

Cal's old friend Terry Marsh (Lennie James) attempts to pull him into a criminal conspiracy after he settles Terry's gambling debts. The criminals abduct both Cal and Terry and try to recruit Cal to be their personal lie detector, forcing him to determine the validity of a client's counterfeit bills. Over the course of the episode, it is revealed that both Terry and Cal got into trouble with the police when they were young, and that Terry volunteered to take all the blame, allowing Cal to continue with his life. The event ends with an FBI raid, and Lightman tells Terry that they're even. Meanwhile, the Lightman Group probes murderous threats against a high school. They determine that the threats were made by Stacey, an overweight student, who is suicidal due to emotional attacks by her classmates and gym teacher. After Stacy attempts to overdose in the bathroom of the Lightman Group, it is revealed that the gym teacher instigated and participated in the emotional attacks against Stacey. Jasmine, one of the bullies, gives a genuine apology to Stacey, and corroborates Stacey's accusation. The gym teacher is arrested for obstruction of justice because he received the threats and did not report them

Cal spends the holidays in Afghanistan, where he relies solely on an American expatriate to help a mission to find a pair of missing Marines.

A protesting farmer called Harold Clark parks his tractor, which he claims is filled with explosives, near the US Treasury building. The FBI sets up its command center in the Lightman Group offices, and Lightman tries to find out if there is actually a bomb in the tractor. The FBI wants to blow up the tractor and kill Clark, just in case Lightman cannot find out for sure. Meanwhile, Loker plays babysitter to third-graders stuck in the Lightman Group office, and earns a kiss from their teacher.

Lightman is called upon by a prosecutor to testify as an expert witness in the trial of a beautiful widow accused of murder. The widow is accused of murdering her much older billionaire husband. She is also accused of having an affair with her step-son and stealing from her husband's company. It is a national case that pits Lightman, working for the prosecution, against his ex-wife, who is the defense attorney in the case. Foster, meanwhile, coaches the prosecution witnesses on how to behave on the stand, and how to engage the jury. Loker and Torres discuss her involvement with an older person.
Melissa George guest stars.

Lightman helps a traumatized soldier who got back from Iraq and who thinks that someone is trying to kill him. Lightman exposes the real truth of what happened during the episode that earned the soldier a Silver Star.

The Lightman Group investigates when a young woman is killed at a political rally in Virginia.