As people across the globe are experiencing hallucinations, MI5 agent Zoe contacts Bill for answers; Catherine Durand detects unusual black hole activity.

As Adina starts the next stage of her plan, astronauts Juliet and Richard see warning signs in space; uncovering Adina's sinister mission.

With Richard's help, Catherine discovers she can travel to another world; a new revelation puts Martha's loyalties to the test; Zoe breaks Bill out of prison.

Super villain M.O.D.O.K. runs his evil organization AIM into the ground and is forced to sell it to the tech company GRUMBL. As the megalomaniacal M.O.D.O.K. struggles to regain control of AIM, he risks losing something even more important…his family!

In a bid to save his marriage, M.O.D.O.K. takes Jodie back in time to a concert they missed when they were in college. During a detour to kill the child-version of his GRUMBL boss, M.O.D.O.K. and Jodie are attacked by college-aged M.O.D.O.K., who accidentally absorbs their time crystals, stranding them in 2002. The couple reconciles but is stuck in the past until they catch up to the present. Once in the present, they prevent themselves from ever going to the past in the first place, erasing their entire adventure from the timeline.

With Richard's help, Catherine discovers she can travel to another world; a new revelation puts Martha's loyalties to the test; Zoe breaks Bill out of prison.

Tom grapples with a betrayal and encounters a familiar face; Catherine looks for a solution to the dangers of the black hole.

Owen and the 126 crew race to a gender reveal party gone horribly wrong, and a father/son trapped in a cave during a spelunking excursion. Meanwhile, Owen helps T.K. reconcile the past to help his future, Judd and Grace aid Judd's aging father and Michelle learns the full truth about her missing sister, Iris.

Owen helps T.K. reconcile the past to help his future; Judd and Grace aid Judd's aging father; Michelle learns the full truth about her missing sister, Iris.

Beckett and Castle are followed by a documentary crew as they investigate the murder of a rock star.

In the aftermath of a disastrous "Meet the Parents" dinner, a bickering Castle and Beckett are sent to retrieve the only witness to a murder.

When an up and coming DJ is killed at a pop star's album release party, Beckett and Castle must dive into the raucous world of New York's music industry.

While investigating the murder of a young woman, Castle and Beckett find evidence that links her death with Senator William H. Bracken, the man responsible for Beckett's mother's murder.

Joins the BAU team, which is tasked with capturing a killer who escaped prison with 13 other convicts at the end of last season.

The BAU welcomes back Emily Prentiss as they are called upon to investigate the disappearance of three women.

When a young woman is mysteriously murdered, Beckett and Castle discover her death may be linked to a repossessed storage unit up for auction.

In the aftermath of a disastrous "Meet the Parents" dinner, a bickering Castle and Beckett are sent to retrieve the only witness to a murder.

When a bearded, rotund man in a red Santa suit with an ID reading Kris Kringle falls from the sky in Central Park, Castle and Beckett are on the hunt to find the person who killed Santa.

A drunk college student discovers the dead body of a Secret Service agent just before a presidential visit to the area. Booth is ready to hit the ground running and turns to Secret Service agent and former colleague Brandt Walker for information, but is surprised to learn the Secret Service has reservations about Booth's involvement in the case. The team uncovers some shocking evidence that heightens the seriousness of the case, causing Booth to step up for his country. Meanwhile, Brennan is out sick with the flu and former intern Dr. Colin Fisher returns to the Jeffersonian to run lead on the case, but Brennan refuses to be kept out of the loop. Also, Hodgins takes his life into his own hands and turns a corner after a potentially dangerous experiment.

With Cam's reputation and career on the line, the team travels from overseas to help her solve the case of an unidentified young boy; the Forensics Anthropology Unit lost much of its vigor after disbanding to pursue personal ventures, and it will take the collaborative energy and knowledge of the newly reunited team to unravel evidence, and find closure for the family of the unknown boy.

When the remains of a couple are discovered in a cave at National Park, the team must piece together the identity of the man and the woman as well as solve the crime; and Booth's girlfriend and Afghanistan-war correspondent Hannah Burley makes a surprise visit, causing Brennan to re-evaluate her own relationship with Booth.

When JJ arrives home shaken after a rough case, she breaks down and tells her husband about the abduction of two children.

The BAU team searches for a serial killer along the Appalachian Trail in rural Virginia.

Harrow and Fairley are sent to a double-fatality in Fairley's hometown - a trip that will test their already-strained relationship.

As Harrow and Grace investigate the death of a popular health and wellness vlogger, Harrow agitates for the exhumation of Chester's remains.

R.J. unravels the truth about a Little League coach whose family is being mysteriously targeted; R.J.'s parole officer worries that he is pushing the boundaries of his conditional release.

Owen helps T.K. reconcile the past to help his future; Judd and Grace aid Judd's aging father; Michelle learns the full truth about her missing sister, Iris.

While investigating a shocking ritualistic murder, Beckett and her team uncover surprising evidence linking Castle to the killing. As the evidence against him mounts, loyalties are tested, and when surprising revelations come to light, Beckett begins to wonder how well she really knows her new lover and partner of four years.

Castle and Beckett take on a murder at a sci-fi convention.

When a bearded, rotund man in a red Santa suit with an ID reading Kris Kringle falls from the sky in Central Park, Castle and Beckett are on the hunt to find the person who killed Santa.

Booth and Brennan are called to investigate decomposed remains found at the Jersey Shore. The team grows fond of Booth's girlfriend, Hannah, and Angela tries to keep her pregnancy a secret.

The BAU investigates if bullying may be the link between two high school students who are the sole survivors after both of their families are killed.

When a blimp suffers mechanical failure and its engine catches fire, Athena and the 118 must rescue victims both inside and outside a packed sports stadium. Bobby and Athena drop off May on her first day of college and discuss honeymoon plans, while Maddie and Chimney go to couple’s therapy.

In the powerful conclusion of a two-episode story arc, when the FBI fails to get his daughter back, Castle takes matters into his own hands, reaching out to a shadowy fixer to help him recover Alexis.