After a dinner where Cat introduces Vincent to Heather ends badly, Heather enlists Tess to stage an intervention with Cat. Evan receives an interesting proposition that could change the course of his cross species investigation and at an event to honor Joe, Heather goes missing and Vincent is forced to make a tough decision that saves her life.

When secrets about Cat’s family are revealed, it will change everything Cat knew about her past. Vincent finds himself staring his demise in the face; while Gabe takes drastic measures get some answers.

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.

When Catherine’s dad gets remarried, the bride-to-be and her bridesmaids try to find the daughter-of-the-groom a date for the wedding. Uncomfortable with being set up, Cat reluctantly admits that she’s seeing somebody and confides to Vincent that she wishes he could be her date. At the wedding reception, Cat learns about a research grant that Evan received to study the mutant DNA cells found at local crime scenes. When she tells Vincent about Evan’s theory of how the cells are changing to become more animal-like and less human, she encounters an unexpected detour that could change the course of their relationship. Meanwhile, Tess and Joe cross the line romantically despite the fact that Joe is a married man.

Cat and Vincent are unsure if they can trust Alex (Bridget Regan) with the truth about his past. Evan realizes that Claire (Kelly Overton), the woman he is dating, is hiding things from him. Heather (Nicole Gale Anderson) meets and falls for Joe's younger brother Darius (Christian Keyes), and Vincent tries to win over Cat with romantic gestures for Valentine’s Day.

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.

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

Cat is forced to reveal things that she had been keeping from Tess to salvage their relationship, and to protect Vincent. Gabe is suspicious of everyone in the department, while Evan witnesses Cat doing something that changes his opinion of her, making him even more determined to track down the beast.

Evan confesses his love to Cat and admits that he tipped off Muirfield to Vincent’s whereabouts. Meanwhile, Gabe finds evidence that someone in the department is a mole who was working with the vigilante.

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.

After taking their relationship to a new level, Cat and Vincent are forced to deal with reality when someone appears to be the framing the vigilante. Evan finds proof that Cat knows more than she is letting on about the beast. Muirfield and the police are closing in on Vincent and this time there is no escape, so J.T. and Cat come up with an extreme solution. Meanwhile, Tess following a tip, finds something that will forever change her relationship with Cat.

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.

New Assistant District Attorney Gabe Lowan arrives at the precinct, suspicious that cases involving the vigilante are being mishandled, and wanting answers. Cat is determined to protect Vincent at any cost, which includes tracking down a witness and threatening him at a gala masquerade ball. Meanwhile, Vincent worries he may lose control if he gets romantically involved with Cat.

Cat and Vincent go on a date out in public in an attempt to be a normal couple, which backfires on them. Meanwhile, Gabe reveals some information that gives Cat hope they can find a cure for Vincent.

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.

On the anniversary of her mother's death, Cat asks Gabe to attend her family's annual remembrance of Vanessa, which makes Vincent incredibly jealous. Cat learns some information that makes her think her mom might still be alive and when a sniper shoots the mayor at a public event, Vincent finds evidence that links Gabe to the sniper.

Cat suspects Muirfield might know Vincent's whereabouts and in spite of her vow to go cold turkey, she is forced to interrupt his romantic cabin getaway with Alex in order to save their lives. Meanwhile, Evan finds a bug in his lab and becomes increasingly suspicious of J.T..

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.

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.

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.

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.

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.

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.

Cat is placed on leave after interfering in a murder investigation. Meanwhile, J.T. fears that Vincent will become exposed.

Vincent helps Cat investigate the suspicious death of a ballerina. Meanwhile, Tess makes a surprising discovery about the man she's dating.

A homicide detective teams with a man who takes on incredible but uncontrollable strength when enraged. In the series opener, the two meet for what they discover isn't the first time.

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.

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.

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.

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.

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.

Vincent revives a 19-year old boy who was left for dead in a dumpster and rushes him to the E.R., where he remains in a coma. After Evan declares that the boy's x-rays reveal a history of bone fractures, Cat and Tess question the father, Zachary Holt, who worries that his son's ADHD and history of fighting and gambling might have gotten him mixed up with the wrong crowd. The detectives question Lois Whitworth, who owns the Westchester Polo Club where the boy worked. Lois is surprised to learn that her daughter, Clarissa has been dating this young man. Clarissa claims that she ended the relationship because he was involved in illegal activities, but Cat and Tess suspect that there's more to her story. Meanwhile, Silverfox and his Murifield agents track down Cat, and offer to tell her the truth about her mother in exchange for turning over Vincent, who they insist is a monster. Cat tells Vincent about her Silverfox encounter, and Vincent realizes that Cat might be afraid of him. JT wants them to flee, but Vincent refuses to leave Cat, instead offering to surrender to Silverfox in exchange for Cat's safety.

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

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 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.

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.

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 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 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.

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.

Gabe comes clean to Cat that he knows about Muirfield. Vincent does not think Cat should trust Gabe and is suspicious of his intentions, which causes tension between them. Meanwhile, JT and Vincent finally find a new place to live.

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.