Allan Hawco returns for a fourth season as Jake Doyle, the rogue PI with a penchant for getting himself into dangerous situations; but this time he's doing it without the person his heart longs for... No, not Des. Sgt. Leslie Bennett (Krystin Pellerin) is missing from RNC Headquarters and Jake isn't getting any clear answers. That's because Leslie has been sent undercover, tasked with gaining the trust of one of St. John's' most ruthless drug dealers. When Jake and Leslie find each other, their moments are fleeting, and they realize what it's like to not be able to lean on each other when the pressure's really on. With Leslie getting deeper and deeper into her undercover world, we find ourselves wondering if she is in danger of losing herself - or her life - completely?
Meanwhile, Mal (Sean McGinley) and Rose (Lynda Boyd) watch as the youngest of the Doyle clan, Tinny (Marthe Bernard), begins to follow in her family's footsteps - enrolling in the RNC Cadet Program. However, she finds herself distracted as she struggles with the recent knowledge that Kevin Crocker (Paul Gross) is her father; But, like a true mini-Jake, she chooses to embrace her fears by visiting Crocker in prison, creating much tension in the Doyle world and leaving everyone wondering how this newly formed relationship will play out.
The fourth season brings with it some exciting new characters who shake up the Republic in fine style. Officer Monica Hayward (Patricia Isaac) is the newest member of the police force and she's determined to make a name for herself, even at the expense of one Jake Doyle. As if that wasn't challenging enough, Jake must also contend with local drug slinger Taylor Gossard (Joel Thomas Hynes) who has his eyes set not only on taking his business to the next level, but on Leslie Bennett as well.
Some familiar faces will also be making return visits, including former love interests Nikki Renholds (Rachel Wilson) and Allison Jenkins (Michelle Nolden), old friends like Jimmy O'Rourke (Scott Grimes) and Wolf Redmond (Alan Doyle), as well as formidable adversaries like Maurice Becker (Gordon Pinsent), Al Kavanagh (Robert Joy) and Kevin Crocker (Paul Gross).
New faces such as Angus Macfadyen, Erin Karpluk and Max Martini light up the Doyle universe, all helping to make for an incredible Season 4 of Republic of Doyle.