After Charlie and Amita get married and begin preparations for their London adventure, they put a slight hold on their wedded bliss when they assist the team in helping Don track down the whereabouts of his gun after it goes missing.

The team investigates the deaths of two men who were part of a group of friends that had been sexually assaulted by a teacher when they were young boys. Also, Charlie and Amita get a fantastic job opportunity that could put a wrinkle in their wedding plans.

The team gets a taste of the limelight when they search for jewels worth millions that have been stolen during an awards show broadcast. Also, Don revisits an old case that is haunting him, and Larry returns from his adventure in the desert.

The team searches for a serial killer who is targeting men that solicit prostitutes. Also, Colby and Nikki deal with the aftermath of a car crash when they have an accident during the investigation.

The team searches for a lost shipment of high-caliber firearms when one of the weapons is responsible for random killings throughout the city. Also, Charlie and Amita disagree on a wedding date while Don re-evaluates his relationship with Robin.

Don and the team try their luck at investigating the theft of scratch-off lottery tickets, but the stakes are raised when one of the culprits killed at a botched robbery turns out to be a former lottery winner.

When the team foils a robbery of an armored car full of Federal Reserve money and recover bills that trace back to the infamous D.B. Cooper heist, they call on Agent Roger Bloom, who worked on the Cooper case, for help with the investigation.

When robbers hit a diamond exchange and take hostages, Don and the team find an unlikely ally in convict John Buckley, who may help the team's investigation when they believe the men are copying Buckley's criminal strategies.

While tracking down a felon running a heroin ring inside a prison, Agent Ian Edgerton becomes a murder suspect when the informant he meets with ends up dead, sending a desperate Edgerton over the edge when he takes a member of Don's team hostage.

The team conducts an undercover sting to locate a cyber crime lord, but the operation is foiled by a charming, brilliant hacker whose desire to take over the online black markets puts him in a dangerous online turf war that could lead to murder.

When strange, almost paranormal happenings are observed at a decommissioned air base, the spooky occurrences take on a decidedly different tone when the team is brought in to investigate the mystery of a dead woman found there.

The team searches for a geneticist's daughter who they suspect was abducted by her unstable mother, but become more concerned when they think the young girl may be a clone. Also, Charlie and Amita talk about having kids, and Liz reveals a dark secret.

Don and the team investigate a series of murders which they realize are being copied from scenes out of a soon-to-be-released movie. Also, Larry leaves to embark on his personal adventure.

Don and his team are called in to investigate who is behind a deadly gambling ring that is running a high-stakes Russian roulette tournament. Also, Don and Charlie become concerned about Alan's financial health.

When two FBI agents, part of a unit headed by Don's former mentor, are killed during a shootout with bank robbers, the team must investigate what exactly happened. Also, Charlie and Amita worry when Larry opts not to attend a conference in Geneva.

Don and the team must protect high-profile activist Benjamin Polk at a political rally, but it soon becomes a manhunt when they search for a sniper trying to kill Polk. Also, Charlie awaits an answer from Amita about his marriage proposal.