A young woman comes to The Doyles with one case – to find her unknown biological father – but they end up solving three; Jake is distracted by Leslie while trying to extract himself from Nikki.

The Doyles take on a cold arson case for Mal’s old flame to find out the tragic truth of what really happened when a girl died in a bar fire; Jake and Leslie are finally starting to connect when Jake discovers he might be… a daddy?

A wrongfully convicted murderer gets out of prison and offers the Doyles a generous payday if they find the real killer; Jake finds out the truth about Nikki’s pregnancy.

The Doyles start trailing a potentially cheating husband to find he deeply loves his wife but is in deep trouble with some menacing criminals and smugglers; as Nikki moves forward with her new beau, Jake and Leslie take it to the next level.

The Doyles show their sentimental side as they help Jake’s high school girlfriend run off into the sunset with her new husband, who’s running from both bad guys and good guys to just get away; Rose’s past comes back to haunt her in the form of her ex-con husband, while Leslie weighs whether or not she wants Jake in her future.

A grieving widow hires the Doyles to find out why her husband left a generous sum of money in his will to a woman she’s never heard of. Rose continues to battle with Martin over their divorce while Mal formulates a plan to get Poole out of their lives for good; and Leslie and Jake hit a comfortable stride as friends and colleagues - just as his divorce from Nikki becomes final.

When a dubious chip truck owner notices his truck is missing - along with his driver/best buddy - he cons Jake into taking the case; Martin really crosses a line with Rose and she takes matters into her own hands; and Jake’s divorce becomes final and he’s happy to tell Leslie that he’s now a free-agent. But Leslie’s just been bumped up the ladder with a promotion to Sergeant, and her eye is on the job, not Jake Doyle.

When Mal suddenly leaves town and lends Jake out to be shadowed by a pompous crime novelist looking for inspiration, Jake’s entire life, including his constant relationship woes, is put under the authorial microscope; a simple cheating spouse domestic case turns out to be something far more devious than it first appears; and Jake, expecting the return of his father, gets an unwelcome surprise when it’s not Mal standing in the kitchen to greet him but his troubled older brother, Christian.

Tensions are at an all-time high with Jake's older brother Christian back in town and the Doyles are on a case involving Walter's soon-to-be brother-in-law.

After getting a call from his brother Christian, Jake must help prove him innocent in a shady murder case. Meanwhile health issues creep up on Mal and Des along with Tinny take on a case by themselves.