The service offered by The Lightman Group is truly unique. Simply stated, they can tell if you're lying. It's not the words you speak that give you away, it's what your body and face have to say. Dr. Cal Lightman and his team are experts at reading micro-expressions, the fleeting tics that express, non-verbally, what we are really feeling. With their finely honed interviewing and investigating skills, they have an uncanny ability to dig up the truth.
Cal is approached by a young woman who claims she saw a murder in a vision, but the police won't believe her. Meanwhile, Ria interviews a Supreme Court nominee for the White House to determine if there are any skeletons in his closet.
Zoe enlists Cal and Ria to help prove that her client, a 22-year old college boy charged with statutory rape, had no idea the girl was only 16. Meanwhile, the IRS believes a group claiming to be a religion is a fraud and hires Gillian and Eli to investigate.
A man from the American Embassy in Mexico asks Cal to "unofficially" investigate the disappearance of an American woman after local police refuse to look into it. Meanwhile, Cal's rival, Jack Rader, works with Gillian to identify the person responsible for tainting the blood bank supply when several patients become seriously ill, and one dies.
Emotions run high when Eric Matheson, accused of murdering his wife, takes the Lightman Group hostage to force them to help him uncover the real murderer.
When Cal's old pal, Terry Marsh, comes to town, he brings plenty of trouble with him. Meanwhile, the rest of the team meets with some students from a prep school to determine if any of them are responsible for a threatening tape that was sent to the headmaster.
Ben gets into a bind when he refuses to testify against a Wall Street mobster from one of his undercover cases. Without Ben's testimony, the mobster will go free, unless Cal and Gillian can figure out what Ben is trying to hide. Meanwhile, Ria and Eli work on figuring out who leaked the whereabouts of the original witness and got him killed.
Cal and Gillian help a teenager who believes he was abducted as a baby. Meanwhile, a store owner hires Eli and Ria to help determine if the store was negligent after a stampede of holiday shoppers leaves two people dead and several others injured, triggering a $20 million lawsuit.
Just before Christmas, Cal is sent to Afghanistan to interrogate an American soldier-turned-traitor in hopes of learning the whereabouts of two American marines captured by the Taliban.
Despite being "banned-for-life," Cal heads to Vegas when he is summoned by a casino owner after the star contender in the World Series of Poker goes missing right before the tournament. Meanwhile, Ria analyzes the expressions of the woman Eli is dating to determine if she's "into him."
A farmer, angry about being foreclosed on, protests by parking his tractor, packed with explosives, right in front of the US Treasury building. Meanwhile, a group of third-graders are brought in by their teacher to find out who stole the class turtle.
While giving a talk to some college students, Cal matches wits with a dangerous sociopath who always seems to be one step ahead of him. Meanwhile, Eli and Ria get the run-around from the government when they look into a UFO sighting.
Years earlier, Cal worked on a botched CIA case that resulted in the death of the wife and young daughter of an Irish terrorist named Doyle. Now Doyle was back in town, seeking answers and revenge. This incident leads up to Cal and Gillian meeting for the first time.
Cal is hired by the DA to be an expert witness at the trial of a beautiful, young woman charged with murdering her high-powered, and much older, billionaire husband... and Zoe is representing her. Meanwhile,Ria lets Eli in on a little secret.
Cal uses virtual reality and other unconventional therapy to help a war veteran get to the root of the cause for the severe PTSD he's been plagued with since returning home from the Middle East.
After being shot and left for dead, a police officer spends the last few hours of his life paralyzed, unable to move or speak, before finally succumbing to his injuries. Hoping to get some shred of information that may lead them to the people responsible, the FBI brings in Cal to see if there's any possible way to read a person who can't even move his eyes.
Ria hasn't seen or heard from her little sister, Ava, since she was sent to a juvenile detention center, so when she receives a message from Ava, desperately pleading for help, Ria, Cal, and Gillian run to the rescue.
At a ground-breaking ceremony for a new community center, an assassin's bullet misses the governor, killing a young female staffer instead. When the governor jumps nine points in the polls, Cal immediately suspects the governor, or someone close to him, for what he calls a "bullet bump."
Cal involves his team in a cover-up when a fighter from an underground extreme boxing fight club for illegal aliens is murdered.
Cal and Zoe attend the execution of a man they helped put on death row. Moments before dying, the murderer claims to be innocent... and Cal believes him. Racked with guilt that he might have sent an innocent man to his death, Cal defies orders from the FBI to stay out of it and goes in search of answers.
When Gillian's boyfriend, Dave Burns, gets abducted, Cal attempts to track him down with the help of Burns' mysterious ex-partner.
A distraught father comes to Cal for help finding his 18 year old daughter who disappeared and then turned up in a porn movie. Meanwhile, Cal pits Eli and Ria against each other as they vie for the same promotion.