Three months after Vincent Keller was abducted by Muirfield, Detective Catherine Chandler, is reunited with him - but not in the way she planned. He's changed: his scar has disappeared, his memory has been wiped clean and he returns as a supercharged beast on a mysterious mission. Catherine needs to unravel the reasons behind Vincent's change if she has any hopes of recovering their epic love, while also trying to solve the secrets that swirl around her own life.

Vincent kidnaps Cat as she tries to learn more about his mission; J.T., Tess and Gabe work together to help Cat.

Catherine and Vincent track a mysterious beast while keeping their individual agendas from one another in a clever game of cat-and-mouse. Meanwhile, Heather has a bombshell revelation for Cat, and Tess confronts Gabe about his real motives for helping Cat.

After getting stonewalled by Cat in his quest to track down a suspected beast, Gabe enlists Vincent's help, but Vincent quickly takes matters into his own hands. Unfortunately, the beast as an advantage over Vincent that requires Cat's help, in addition to the help of someone else who opens up old wounds from Vincent's past.

Cat uncovers more of her past than she anticipated at her high school reunion; Vincent reunites with a military friend who has a dangerous secret.

Cat confronts her birth father about the mysterious role he's played in her life, while Vincent has to neutralize a high-profile beast. In the process of doing so, Vincent finds himself rescuing Tori, a damsel in distress, who may be the key to completing his mission.

In an attempt to find out who Vincent's handler is, Cat enlists in the help of her father and invites Vincent to Thanksgiving dinner, which ends in disaster.

Vincent and Cat find themselves at odds on how to deal with Agent Reynolds, which forces Vincent to wonder if he is more beast than man. Cat makes a drastic move that will forever change her relationship with Vincent.

In order to prevent Vincent from further injuries, Cat helps protect Tori when her life is threatened, revealing a new, unexpected mystery. Meanwhile, Vincent's stubborn attempt to intervene leads to life-changing consequences, which causes Gabe and Cat to grow closer.

Vincent goes on a national talk show to reveal he is still alive, while Cat dives into an undercover case for FBI Agent Dana Landon. Vincent, determined to learn more about his beastly origins, ends up coming face-to-face with Cat in the middle of a heist, which forces them to work together.

A group of criminals looking to steal a rare necklace in Tori's possession takes Cat, Tori and Tess hostage at the precinct, leaving Vincent as their only hope for help. Vincent is forced to make a decision since helping could reveal his true identity to the entire force.

Cat and Vincent must work together to save J.T. when he gets kidnapped, while Tori attempts to intervene, with fatal consequences. Meanwhile, a stranger from FBI Agent Dana Landon's past is rescued along with J.T., and might have some insight about Vincent's beastly past.

In an effort to track down Sam’s captor, Vincent and Cat have to work together on Valentine’s Day, which forces Cat to evaluate whether she wants to be in a relationship with Gabe.

When some of Gabe’s acquaintances go missing, Cat and Vincent must come together to save them. Vincent ends up returning to the hospital where he was an intern, allowing him to see what his life could have been.

Feeling pulled between her current boyfriend and her ex, Cat has to decide between Gabe and Vincent. While Cat and Vincent work together to save Sam’s latest victim, Cat’s decision gets complicated when she and Vincent find themselves in a compromising situation.

Cat and Vincent must revisit a romantic destination as they try to prevent Sam from destroying a group of people.

Vincent has just been arrested for murder and Cat is afraid he'll get a life sentence. Fearing that she may die if she loses him again, she comes up with a plan to help him escape from prison and save him.

A city-wide manhunt for Vincent forces him and Cat to stay under the radar; Vincent and Cat find a surprising ally when the FBI asks them for help with an important case.

Gabe suspends Cat and Tess from the squad in order to force Vincent out of hiding.

Cat and Vincent take Agent Knox's offer to extricate and try to lead normal lives -- but forces out of their control conspire to expose them and drag them back into the fray.

Desperate to start over with Cat, Gabe tries to woo her by taking her on a romantic date. However, she has plans of her own regarding how to save Vincent – while also trying to plan Heather's bachelorette party.

Cat finds information in a surprising place -- her ancestor's journal -- that makes her think the only way to stop Gabe is to kill Vincent.

Vincent considers popping the question. The timing may not be right, however, when Cat stumbles upon an unusual case involving a superhuman rampage. In other events, Tess believes JT—who doesn't understand how he's still alive—has a mental block to recovery.

Vincent moves in with Cat which forces them both to address the rapid changes in their relationship while they investigate a shocking new lead in their hunt to track down who is behind the super-human experiments. JT tries to impress Tess’ brothers and discovers that there may be some side effects to the medicine he received from Agent Thomas. Meanwhile, Heather returns to town with a surprise announcement.

When two married agents from the FBI take over an investigation, Catherine and Vincent hope they are seeing a future version of themselves but fear their work schedules are jeopardizing their relationship. When the two couples bond and team up on the case, a mysterious coincidence surfaces that raises suspicions. JT investigates whether he has super powers of his own while Tess considers a career move. Meanwhile, Heather offers up an interesting option to make her big sister’s life a little easier.

Cat and Vincent take their relationship to a couples counselor when Cat dives into her work and suspects a wealthy transplant recipient of being involved with the mysterious experiments on innocent people in the city.

When Cat is assigned to a new partner by Tess, she begins to suspect that Bob and Carol have re-surfaced to separate her from Vincent and hunt them both down. Meanwhile, a transformed JT discovers that his newfound healing ability comes at a terrible cost.

JT throws Vincent a surprise bachelor party. Unfortunately, it is interrupted by a mysterious sniper with his sights set on putting a stop to Vincent and Cat’s interference with the super human experiments. Cat’s family comes to town for a bridal shower arranged by Heather but Cat is distracted by having to visit her imprisoned father to ask for his help.

Vincent and Cat decide to elope in order to draw out a superhuman assassin chasing them. J.T. tries to find a lead on the experiments, and Heather tries to focus at her new job.

Cat is excited to finally walk down the aisle with Vincent, but can’t help worry that the rash of superhuman experiments will ruin her destined moment. Vincent, JT and Tess are determined to do anything they can to keep Cat focused on her big day before all hell breaks loose.

After a force more powerful than anything they have ever encountered ruined Cat and Vincent’s big day, Cat becomes convinced they are in over their heads and begins to doubt their ability to stop the threat, forcing Vincent, JT, Tess and Heather to band together in hopes of convincing Cat of her greater purpose.

When Cat and Vincent make it their mission to capture Liam, they find information about a Patient X that they might be able to use to help them find him. Meanwhile, JT and Tess work to confirm that JT is serum free.

In a surprising turn of events, Vincent agrees to help Liam on a mission to retrieve evidence that could expose them both. Meanwhile, a suspicious Cat discovers something about Liam's family history and must warn Vincent before it is too late.

Liam’s shocking history makes Cat delve deeper into the Ellingsworth family, where she learns of their tragic past. Vincent and Cat realize that they will need to use their secret weapon if they want to take Liam down. Meanwhile, JT has a theory about how to save himself but it involves none other than Liam.

Cat and Vincent will be forced to work together as a couple in ways they never have before if they hope to defeat their destined foe in Liam, who will do everything he can to expose Vincent as a beast in order to destroy their love. Season Finale.