This week in Dog River, Oscar is investigated for possible past irregularities in his payment of fuel taxes; the town is shocked about the new coffee policies in effect at The Ruby.
The episode opens with Brent having a coffee at The Ruby. When he asks for a refill, he comments to Lacey about how her aunt had a 'free refill' policy, and tells her that a person could get 30 or 40 refills for the price of one cup of coffee. Lacey is shocked, asking if he really expects to get that much coffee for $1.50; the new price shocks Brent. Later on, Davis and Karen are having coffee at The Ruby, and when Lacey gives them a bill for $3.00, Davis is shocked, telling her that it used to be free, as thanks for keeping the peace. Lacey, noting that Dog River is pretty peaceful, decides to take her chances, and charges them anyway. Karen offers to pay and this only angers Davis more. Hank, too, expresses surprise at the new, higher price of coffee.
Davis, as a way of working out his anger over the coffee, starts handing out a lot of parking tickets. When Karen asks why, he tells her that she broke the code by offering to pay for the coffee, and that because she went against him, she's in danger of being shunned. Meanwhile, at The Ruby, Lacey warns Marvin before he orders that he'll have to pay for his coffee; Karen comes in and asks Lacey to give Davis free coffee. When Lacey explains the situation to Marvin, he gives her some free tax advice on how to deal with the situation as a write-off for promotion and advertising, allowing her to give Karen and Davis free coffee again. Lacey tells Davis that coffee is free again, giving him his money back, and Davis is happy again.
The main story line involves Oscar's taxes. This story begins with Brent greeting a customer at the pumps; the customer begins asking questions about Brent's name and whether he owns the station or not, then revealing that he's with Canada Customs And Revenue and is looking for Oscar, but can't tell Brent what it's about. Brent lies and says that Oscar went to Hawaii, then corrects it to Red Deer (Alberta), but just then, Oscar comes in yelling about Brent having left the dumpster lid open. Marvin Drey, the taxman, introduces himself to be greeted by Oscar with hostility and yelling. Brent tries to be helpful, but Oscar won't listen to reason.
Oscar approaches Hank for help with his tax problem. They discuss it in The Ruby, not realizing that Marvin the Taxman is sitting in the booth immediately behind them. Hank comes up with a plan to blackmail the Taxman by getting him drunk and getting pictures of him doing something sleazy; he also has an alternate plan of getting the Taxman drunk, then showing him papers which they'll mess up, thus embarrassing him, and then he'll let Oscar off rather than admit he was drunk. Brent says that the plan doesn't sound too good but Oscar likes it. Wanda suggest that maybe he should just look for the tax receipts.
Oscar starts looking for the tax receipts, but won't listen to Emma when she tells him where they are, preferring to rummage around everywhere but the right place.
At the bar, Brent thanks Marvin for helping Lacey and buys him a drink. Marvin tells him that the problem isn't really a problem, they just need to know why Corner Gas is selling so much gas, and Brent has a logical explanation for this - they're the only station for 60 kilometers and on two major trucking routes. Marvin says that if it all adds up, then there's no problem. Hank comes in and suggests that he and Marvin have a few drinks then run down the street with no pants on. Oscar shows up with the box of receipts that Emma found for him. Hank, not realizing that these are the real receipts, moves on to the second plan, messing the papers up and incurring Oscar's wrath. Marvin happily begins looking through the receipts, and all is well again in Dog River.