The film opens with Hank Yarbo dreaming about an armed robbery at Corner Gas, where station owner Brent Leroy and Wanda Dollard turn out to be robots, while the robber shifts into a werewolf that Wanda fights. Hank wakes up with a National Star judge in front of him at the Regina Airport. They depart for Dog River, where the town is in a riot. Hank proceeds to explain the events that caused the town to fall apart.
Five years after the original series finale, Mayor Fitzy has blown the town’s money on a bad real estate investment in Detroit, leaving Dog River without electricity or water. A box that Sergeant Davis Quinton checked on his contract allows the town to force him to retire on his 25th anniversary of police service. He leaves Wanda to watch his house, which—with its two diesel-powered backup generators—is the only place in Dog River with reliable electrical power. Wanda turns Davis’ garage into an illegal bar and later a casino.
Officer Karen Pelly, married and pregnant, begins issuing tickets in order to improve her stats and her job prospects should Dog River close and thus require her to find a job in another community’s police department. Brent’s father Oscar becomes a survivalist and trades his car for a horse-drawn cart, which Karen confiscates and repeatedly returns. An epiphany leads Davis to become a private detective and begin solving anything he can classify as a “mystery.”
After realizing that the crisis won’t blow over and that Lacey Burrows, the owner of The Ruby, will move away if Dog River goes bankrupt, Brent buys the closed town bar and enters Dog River into a “Quaintest Town in Canada” competition, hoping that the $75,000 prize can save the town. Emma Leroy invites Lacey and Brent to dinner to spark a romance that could bring grandchildren, while Hank has a falling-out with Brent after Brent refuses to invest in his Coff-Nuts plan to bring a corporate branch to town.
After Lacey advises a Coff-Nuts representative named Jerome that the town is broke, a woman representing CN Holdings tries to convince the townspeople to sell their homes. Hank overhears the scheme and takes Jerome to Dog River’s rival town Wullerton in hopes Coff-Nuts will change its plans and ruin the rival town. Davis catches up, and the two head back to Dog River amid Wullerton’s unusually friendly reception.
Brent and Lacey struggle to manage repairs and the town’s electricity, while Emma rejoices at the idea of grandchildren and tries to keep Emma’s dinner plans on track. At the bar, Jerome suffers an injury and files a lawsuit against Brent. Wanda volunteers to represent Brent, but loses the case, resulting in Corner Gas being confiscated and the bar condemned.
Fitzy returns with a plan to let Wullerton annex Dog River, a move that proves unpopular. Brent and Lacey rally the town to prepare for Tina Fuller to judge the contest, but a series of mishaps creates the appearance of a riot in the middle of town. The community gathers at The Ruby, where Lacey urges everyone to support Brent financially, though he declines. Tina sympathizes with the town’s plight and writes an article to garner public support for Dog River. The resulting media attention pressures Coff-Nuts to drop the lawsuit. From Wanda’s casino proceeds, Karen’s tickets, and a fundraising drive by Wullerton residents, the town is saved. Catastrophe averted, Lacey and Brent share a kiss in front of the crowd at The Ruby. Oscar encourages Brent to ask Lacey out, but the couple reveal they have been dating for two years. Emma rejoices at the prospect of grandchildren yet is dismayed when Lacey and Brent disclose they have decided against having children.
