When secrets about Cat's family are revealed, it will change everything Cat knew about her past.
Cat and Vincent go on a date out in public in an attempt to be a normal couple.
On the anniversary of her mother's death, Cat asks Gabe to attend her family's annual remembrance of Vanessa.
Gabe comes clean to Cat that he knows about Muirfield.
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.
Cat is forced to reveal things that she had been keeping from Tess to salvage their relationship, and to protect Vincent. Meanwhile, Evan is suspicious of everyone in the department, making him even more determined to track down the beast.
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. Meanwhile, Evan finds proof that Cat knows more than she is letting on about the beast.
Suspicious that cases involving the vigilante are being mishandled, a new Assistant District Attorney arrives at the precinct wanting answers. Meanwhile, Vincent worries he may lose control if he gets romantically involved with Cat.
Evan receives an interesting proposition that could change the course of his cross species investigation. Meanwhile, Cat introduces Vincent to Heather.
Cat and Vincent are unsure if they can trust Alex with the truth about his past. Meanwhile, Evan realizes that Claire, the woman he is dating, is hiding things from him. Bridget Regan guest stars.
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. Meanwhile, Evan finds a bug in his lab and becomes increasingly suspicious of J.T. Bridget Regan guest stars.
J.T. learns that Evan is planning to propose a task force to catch the beast and must figure out how to stop him. Meanwhile, Vincent is torn between his new feelings for Cat and his old memories with Alex.
Vincent barely escapes being caught by his former fiancee, Alex and must deal with the repercussions of his past. Meanwhile, Cat is in the hospital and is forced to confront her feelings for Vincent. Bridget Regan guest stars.
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. Meanwhile, Cat learns about a research grant that Evan received to study the mutant DNA cells found at local crime scenes. Rob Stewart guest stars.
Vincent allows JT to inject him with endorphins and sedatives that force him into a fugue state. Meanwhile, Cat and Tess investigate the attempted murder of a teen pop star.
Cat learns the truth about Vincent's blackouts and thinks he may be involved in the brutal murder of a local college fraternity brother. Meanwhile, JT continues to examine Vincent's condition which causes Vincent to act erratically.