A pub owner in Los Angeles suspects that one of her bartenders might be overpouring for customers, giving away too many free drinks and overtipping himself. To find out, she calls in the Mystery Diners, who outfit the bar with hidden cameras and go in undercover to see what is really happening when the boss is away.
When the owner of The Groves Bar & Grill becomes concerned over a large loss in food and supplies, the Mystery Diners go undercover with hidden cameras as new employees and customers, suspecting that a recently hired chef may be plotting more than just the items on the menu.
Brett and Rose, the husband and wife owners of German restaurant Haus Murphy, disagree on almost everything, particularly the hiring of Rose's nephew as their new restaurant manager. Fearing he is unqualified for the job, the couple hires Charles Stiles and Mystery Diners Danny, Chris and Deanna to go undercover and show them just how incompetent their nephew truly is.
After losing thousands of dollars in unaccounted alcohol and hearing rumors of late-night staff parties, the owner of Big Earl's Greasy Eats contacts Charles Stiles and the Mystery Diners for help. Mystery Diners Shellene and Chris go undercover as a waitress and flirty customer in hopes of scoring invitations to an after-hours bash.
After receiving numerous bad service reviews and noticing a 30 percent decline in revenue, the owner of Caffe Boa contacts Charles Stiles and the Mystery Diners to help him find the cause of his problem. Mystery Diner Danny goes undercover as a waiter and discovers several problem employees who threaten patrons, drink on the job and eat customers' food.
The owner of Amaro Italian Bistro seeks the help of Charles Stiles and the Mystery Diners because he believes his manager is acting inappropriately with the staff and picking favorites based on appearance. Mystery Diners Destiney and Sarah go undercover and interview for a new waitress position to see if the manager will hire an attractive waitress over a qualified one.
Charles Stiles and the Mystery Diners descend upon The Blue Moose, where longtime chef "Grumpy Tom" has a knack for disrespecting everyone in the place, including the newly installed second-generation owner. Mystery Diner Jessica goes undercover as a waitress to prove just how grumpy Tom is and how his attitude negatively affects business.
The owner of Las Vegas bistro 3 Tomatoes & A Mozzarella fears his restaurant manager may not be doing the greatest job in his role. The hardest part -- the manager is his brother. The Mystery Diners will go undercover to see what's really happening and whether this brother is a keeper.