Trouble is a spoiled pup enjoying a lavish lifestyle in a grand mansion, under the care of his affluent, elderly owner, Mrs. Sarah Vanderwhoozie, along with her devoted butler, James](/actor/colby-lopez), and renowned animal trainer Cesar Millan. However, when Mrs. Vanderwhoozie passes away peacefully, Trouble finds himself alone and oblivious to the chaos that ensues. Her niece and nephew, Claire and Norbert, arrive to lay claim to their inheritance. In their rush to sort through the estate, they inadvertently dispose of Trouble, whom they regard with disdain and indifference. To secure their aunt's fortune, this unwilling duo discovers they must establish a bond with Trouble within three days, a task both find distasteful. In a bid to locate him before the deadline, they enlist the help of Thurman Sanchez, a skilled animal tracker.
Meanwhile, having escaped the truck carting away his owner’s belongings after realizing what has transpired, Trouble tumbles into a series of mishaps, including a comical confrontation with a troop of red squirrels that steals his collar, leaving him feeling like a stray. In the bustling city, he encounters a feisty, homeless dog named Rousey while scavenging for a meal from a meat truck, prompting a chaotic chase through a restaurant owned by celebrated chef Ludo Lefebvre. Amid this mayhem, a budding singer and pizza delivery girl, Zoe Bell, loses one of her pizzas. After his nighttime adventures with Rousey in the outdoors, Trouble wanders into a dog park where he meets domestic pups Norm, Gizmo, Bella, and Tippy. They attempt to help him navigate his new life and avoid the danger of being lost forever.
Despite their rocky initial interactions, these new friends rally to assist Trouble, especially when they learn of the squirrel thief. During a confrontation with the pesky squirrels, Thurman finally tracks down Trouble but ends up capturing the squirrel leader, attempting to broker a deal to recover Trouble. While Trouble spends time at Zoe's apartment, she creates a new collar for him and captures his heart with her caring nature. Unfortunately, when the mischief-making squirrels invade her apartment causing chaos, Zoe faces eviction. Sent to the dog pound, Trouble reunites with Rousey and befriends three other strays: Snoop, Otis, and Caramel. Rousey shares her own painful backstory of being abandoned after she saved her owners' child from danger, which sheds light on her wariness towards humans.
As the deadline approaches, Zoe opts to rescue Trouble from the pound, only to find that Thurman has beaten her to it. Determined, she scours the city for him. Realizing the depth of Zoe's affection for Trouble, Rousey teams up with the other strays to assist her, using Trouble’s collar as a tracking device. Eventually, they return Trouble to Claire and Norbert in the mansion, but Thurman plots his revenge with the squirrels after being shortchanged by the twins.
Just as the twins are about to secure their inheritance by deceiving Mr. Macbain, Zoe interrupts, revealing the truth about their unloving treatment of Trouble. In a twist of fate, Thurman seizes the opportunity to leverage Trouble's return against the twins, summoning the squirrels for ransom. However, a thrilling rescue arises as Rousey saves Trouble at the last moment. With the situation laid bare, Mr. Macbain revokes the twins’ claim to the fortune. Ultimately, Trouble is bestowed the choice of his owner, and he joyously selects Zoe. This decision allows Zoe to inherit not only Trouble but the mansion and assets of Mrs. Vanderwhoozie as well, infuriating the twins and Thurman.
In a heartfelt conclusion, Zoe dedicates her newfound wealth to revitalizing the local dog park, renaming it Vanderwhoozie Dog Park, which honors both Trouble and Mrs. Vanderwhoozie. Zoe pursues her dreams of stardom, capturing the attention of singer-songwriter Jason Mraz, while the dogs celebrate with their own heartfelt tribute to Trouble, marking the beginning of their new lives together.
