A high school student is seen running from the home of a murdered teacher. Elsewhere, the chairman of the House Ethics Committee is believed to have been hiring a prostitute.

Cal works on the claim that a sergeant raped a female soldier, while basketball fan Gillian investigates a case in which a college alum used bribery to get him to sign on with the school.

The Lightman Group head to a competitive prep school when a federal judge's daughter is murdered. Meanwhile, a pilot from NASA has been accused of crashing his plane intentionally.

The team is asked to keep watch over an ambassador from South Korea while here for his son's wedding, and is also running for president in his native land and has received assassination threats. During the ceremony a shot is fired and the ambassador's son is hit, which leaves Cal to believe it wasn't just a case of bad aim. Besides, everyone at the wedding celebration seems to have a secret they are hiding.

Ria and Cal question a former gangster. Meanwhile, Eli and Gillian investigate when a firefighter is killed on the job.

Cal and the team look into the practices of a construction site when a building collapses with three men trapped inside.

When Lightman is hired to find a corporate spy at a pharmaceutical company, he discovers a high-level conspiracy surrounding a new drug that could put thousands of lives at risk. The team is also hired by the State Department to assist with negotiations for the release of two Americans imprisoned in Yemen.

While waiting in a traffic jam, Cal realizes that the traffic is stopped due to an accident. He goes to investigate and learns that it was a suicide. However when he sees an old acquaintance that should not be here, he surmises that there is more to it. She tells him that there’s been another suicide in the exact same sport and that thr first one was related to the second one. Cal proposes his help. Eli and Gillian are hired by the SEC to find out if Hollin who has agreed to plead guilty to numerous charges has told them everything.

FEMA Commander Stevens calls the Lightman Group in to help finding three missing construction workers after a building being built collapsed. All the major players, FEMA, Civil Engineer and the mayor blames each other for the catastrophe. Cal finds out very soon that the worker who told them where the three missing should be was lying, they have to stop and let the dogs in. Eli and Ria interview a potential client. Jason McLean, the founder of a very successful networking website, asks them to find out if the woman he is going to marry has lied about what she knew before meeting him. While they usually refuse these kind of cases, the check McLean gives them tips the balance in his favor.

Cal is hired by his ex-wife, an assistant district attorney, to investigate an arson case which a childhood friend, now a famous TV reporter, has been accused as the suspect. His word is based on that of his 5-year old son. Meanwhile, Foster and Torres investigate a drive-by-shooting involving rival rappers.

Cal is hired to investigate when an undercover cop chasing a drug suspect accidentally shoots a teen instead. Meanwhile, Loker’s lie during the recent Ponzi-scheme investigation could come back to bite him when Cal informs him they may become deposed in a lawsuit because of the matter. Also, Cal’s suspicion that Foster’s husband is having an affair is renewed when he spots him with the same woman he had seen him with before.

FBI agent Ben Reynolds, is in pursuit of a serial rapist who is terrorizing the Washington area. He partners up with the Lightman Group for one of his toughest case to date. Lightman infiltrates a prison to meet Andrew Jenkins, a convicted criminal an pathological liar in which the serial rapist may be imitating. Meanwhile, Torres and Loker search the fan mail of Jenkins, while Foster interviews a recent victim of the rapist.

FBI agent Reynolds enlists the Lightman Group to help find the perpetrators of a terrorist attack outside of Washington, DC. For one team member the case becomes very personal. In addition, Cal and Zoe are afraid that their daughter may be in danger.