The team investigates a serial murder case in Bakersfield, California.

The team heads to Seattle to hunt for a murderer whose MO appears to change at random.

A terrorist hacks a passenger's tablet and uses it to take control of the auto pilot of a plane in order to crash it.

Atlanta PD has invited the BAU in for an equivocal death investigation, that of investigative journalist Albert Stillman, who died being run over late one evening as he wandered into highway traffic. An eyewitness who tried to help Stillman just before he was run over states that he was waving his arms in the air yelling, "get them off me", this depiction which goes against Stillman's history of no mental illness. Reluctantly, Stillman's editor, John Carlson, discloses that Stillman was using heroin as medication for a back problem. Stillman was scheduled to meet with a source on a story concerning vaccinations when he vanished for three days just before he died. Garcia learns that another person associated with the case is a Dr. William Suri, a research scientist of entomology, who is later found dead, shot to death. Upon investigation, the team discovers that both Stillman and Suri were abducted - meaning that they are dealing with a serial killer - and had minute bite and deep self-inflicted scratch marks. They thus come to the conclusion that the unsub has delusional parasitosis - the belief that he is infested with bugs - and is looking for people to support his delusion by making them feel what he feels. When they don't support the delusion, he kills them. Based on that theory, the team believes his next victim will be someone in that vein, someone who may have a similar delusion. Locating such people may be easier than getting them to cooperate in the investigation, even if there is the threat of what happened to Stillman and Suri happening to them.

On October 30, 2014, a frightened eleven year old Joshua Parker is found at a Halloween fair in San Diego. He went missing on Halloween day the previous year. His case mimics that of Tommy Wilcox, who went missing on Halloween 2012 in Los Angeles, only to be found on Venice Beach October 30, 2013, alive but he who eventually died of malnutrition a few hours later. Joshua, however, is expected to live. Both boys had atrophied muscles, and had splinters and puncture wounds, although Joshua seems to have been fed somewhat properly. Both boys were also considered troubled, Joshua who was never listed officially as missing since he was a chronic runaway. The problem for the BAU is that Tommy's captor, Rodney Tanner, who confessed to the crime, is currently incarcerated, meaning that he either had a partner, there is a copycat loose, or that his confession is a lie. They have to figure out this issue before another troubled early or pre-teen Caucasian boy is abducted in the next day. Reid comes to the conclusion that the boys were housed in a homemade wooden box, which accounts for all their physical issues. Discovering a case similar from the past of boys so confined, especially as it relates to Halloween, may provide clues as to the identity of the unsub.

The BAU is stumped to find the common denominator among male victims in Montana, making it difficult to profile the UnSub. Meanwhile JJ deals with her feelings about a family crisis.

People in Maryland with large social media followings are murdered by an unsub who takes on the persona of an Internet urban legend. Meanwhile, Morgan and Savannah struggle to find quality time for each other due to their business careers.

A former Boston prosecutor turned successful defense attorney is abducted. As the team probes, past secrets of his life surface.

Rossi encounters an avid follower with an important secret, and a physically and psychologically damaged woman lets loose with personal murders.

The BAU is called to Salt Lake City, Utah to investigate a suspicious triple-homicide. Throughout the course of their investigation, they eventually discover that a fugitive killer could possibly be linked to the UnSub and he could also be a familiar face.

The team head out to Nevada after several frozen bodies are found floating in water somewhere. Whilst the BAU investigate it is revealed the victims were apart of a religious cult which they believe could be responsible for the deaths. Meanwhile, JJ is forced to confront some difficult emotions and demons on the one year anniversary of her abduction, and leans on Reid to help her get through.

The BAU searches Tallahassee for a serial killer who calls the authorities to report the crimes prior to committing them. Also, as Rossi prepares for a weekend visit with his daughter, Joy, he receives startling news about the death of a comrade from the Vietnam War.

The members of the BAU team are brought back to their origins as they look at one of Gideon and Rossi's old cases.

The BAU heads to Indianapolis, Indiana where a bomb has just exploded at a popular chain coffee house, killing several. The police believe this bomb, crudely made using TNT, is related to a bombing one week earlier at a school, also using TNT. That bomb, because it was detonated at night, killed only one, the night time custodian, who was not supposed to be in the school at the time. Based on the exact location of the coffee shop bomb, Rossi and Morgan are uncertain if the bomb was meant to be as deadly as it was or not. In relative terms, there were also some good news stories associated, where a pregnant woman was saved, she who delivered a healthy baby. A third bomb attempt coupled with other information leads to the team figuring out who the bomber is. However, that third bomb, plus the school bomb, provide the biggest clues as to the nature of the entire picture. They hope that planting a little public misinformation may help them catch the unsub.

Peter Folkmore was an abused child and is an abuser as an adult. He captures women and abuses them for not reciting the exact instruction Peter gives them.

Two guards at a privatized maximum security prison in Texas are murdered. The investigation reveals the suspects may be in the prison.

The BAU hunt a serial killer in Wisconsin and try to find a connection between the victims so they can profile and identify the UnSub. Meanwhile, Kate experiences trouble dealing with her niece when she starts acting out.

When the wife of an increasingly prominent Congressman disappears, the BAU investigate and come to consider his adversaries and political enemies as potential suspects of the abduction, or possibly murder.

When an innocent family of four is abducted while vacationing in Barbados, Hotch and Cruz enlist the assistance of the FBI's most elite team in handling international cases. They realize that this situation closely resembles a case that the BAU once handled in Florida. Upon this discovery, the BAU contacts Jack Garrett, (Gary Sinise) the unit chief of the team with whom they will be working. The BAU will need to pool together their skills with Garrett's elite team in hopes to save this family. This will serve as the backdoor-pilot episode for the new spin-off, Criminal Minds: Beyond Borders.

When a family from Maryland is found murdered at their dining room table, the team tracks down other family members and friends to uncover secrets and details from the past in hopes to find out what may have led to it, and to catch who is responsible. Also, Hotch must try to make peace with his father-in-law, Roy, (Ed Asner) after discovering he's been diagnosed with Alzheimer's, and it has become painfully noticeable.

The BAU searches for a suspect who controls minds; the hunt puts one team member in danger.

The team heads to Los Angeles, California where three people have been murdered in two separate incidents over three days, each victim shot thirteen times while sitting in a car or next to a car located in the same crime ridden neighborhood. The ballistics show the same .45 caliber gun was used in both instances. The first victim, Gary Fisher, was known to have frequented prostitutes and was found in area where he was probably meeting with one. Nate Cochran and Tasha Brooks, the second and third victims in the same car, were a john and a hooker. When a fourth and fifth victim are discovered together, they an elderly woman, Clara Miller, and who seems to be a mugger, Lamar Taylor, the team believes the unsub is a vigilante - a moral enforcer - who is looking to clean up the streets of what he sees as immoral behavior. Because of the overkill, they know the reasons for the murders are personal. Information they learn about Clara and Lamar, and the discovery of subsequent victims leads to the team believing the unsub is devolving into believing everyone is a criminal. As such, they have to put together the pieces quickly to find him before more innocent people are indiscriminately killed.

When Kate's niece and her best friend Markayla are kidnapped, the BAU suspects an online predator engaged in sex trafficking who poses as a teenage boy.