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.

Vincent and Cat’s wedded bliss comes to a halt when they learn from J.T. that someone is trying to expose the identities of beasts. While on the hunt to find out who is behind the threat, Tess is reluctant to help since they are all trying to move forward with an attempt at normal lives.

As Cat and Vincent hunt for a black market buyer searching for beasts, they have to protect an heiress whose identity was exposed. Cat and Vincent realize how much they have to lose if Vincent's true identity is revealed.

While attempting to be normal newlyweds, Cat and Vincent grapple with how to overcome the danger lurking. They find themselves in the fight of their lives when their happiness becomes jeopardized.

While working to uncover who is after Vincent, Cat discovers she might be pregnant. A lead Vincent follows puts his life in jeopardy. Meanwhile, J.T. gets kidnapped in a case of mistaken identity.

Vincent and Cat realize they have to go into hiding now that someone is out to kill Vincent. Vincent wonders if Cat would have been better off without him and gets a glimpse into exactly what her life could have been.

Vincent and Cat discover that there is another nemesis out to get Vincent, which brings the gang closer together in more ways than one. Cat and Vincent are forced on opposite sides of the law, which puts their relationship in jeopardy.

With Vincent in hiding and Cat's job on the line, they must re-group about how to bring down the people hunting beasts. Vincent tries to infiltrate a private army, while Cat scrambles to obtain information and hopes that no one at work discovers her ulterior motives.

Vincent goes undercover with a sexy operative, who Cat discovers is an assassin. Vincent has to play both sides, while Cat has to convince DHS she can still be trusted.

Vincent and Cat fight to reclaim some normalcy to their lives, even as the threats of a beast bounty and a DHS manhunt loom. Meanwhile, Tess takes a huge risk by protecting Vincent from a nosy reporter.

Vincent is forced to undergo a series of tests orchestrated by the mystery buyer in order to keep from being exposed. Cat, JT and Heather work to exonerate Vincent.

When Vincent and Cat discover they lost control of their secret, they finally admit it might be time for life on the run. Vincent realizes he must face his past, while Cat worries about how much they have to lose.

Cat and Vincent face a huge setback when Vincent is secretly interrogated about an impending attack, putting Vincent at his breaking point.

Vincent and Cat are prepared to make the final sacrifice to halt an attack and eliminate beast makers from the world once and for all.