Over a lively animated opening sequence, we are introduced to Johnny, a New York City bookie who uncovers incriminating evidence against a powerful businessman. He secures the damning photos and financial records in a bank's safe deposit box, giving the key to his girlfriend, Nikki Finn. However, when Johnny attempts to blackmail the industrialist, he is brutally killed, and his body is concealed in Nikki's car trunk. In a twist of fate, Nikki is arrested for his murder. The judge determines it as a crime of passion, sentencing her to a seven-year term in the Rockford Correctional Institute for women.
Fast forward to four years later, Nikki earns early parole for good behavior. As a condition, she is required to return to her hometown, Philadelphia, to complete her parole. The narrative then shifts to Loudon Trott, a tax attorney played by Griffin Dunne, who is on the verge of marrying Wendy Worthington (Haviland Morris), the daughter of one of New York's wealthiest men, Simon Worthington. Loudon juggles his duties imposed by Simon, who unexpectedly instructs him to pick up Nikki upon her release, simply referring to it as a charitable endeavor known as "Operation Prisoner Shuttle."
During his fateful drive to collect Nikki, Loudon makes an unexpected stop at the docks to collect a package for a client, only to realize it contains an exotic cougar named "Murray." With the wild cat secured in a cage in his Rolls Royce, he fetches Nikki from prison. Upon her release, Nikki insists on making a detour to a shopping mall to grab gifts for her family. However, police detectives are trailing her, hoping she’ll lead them to Johnny’s evidence and unveil the real murderer.
At the mall, Nikki upgrades her wardrobe, engaging in a little mischief by shoplifting music tapes, inadvertently causing a distraction that allows her to escape with the stolen items. As they leave the mall, Nikki adamantly refuses to leave town without purchasing a gun from a dealer in Harlem, a connection she made during her incarceration. Loudon reluctantly obliges, letting her take the wheel of the Rolls Royce. However, her reckless driving prompts police intervention, leading to Loudon being hospitalized, mistakenly believed to be suffering a heart attack. While he is out cold, Nikki deceitfully claims to be his wife, swiping his wallet and clothes before fleeing in his car.
Upon recovering, Loudon utilizes a taxi to chase after Nikki and soon encounters chaos, finding his battered Rolls Royce being vandalized and scavenged. In a riveting turn of events, he catches Nikki in the middle of a gun purchase. Amidst a police raid, they narrowly escape, and a series of misadventures ensues, including a hasty retreat through an apartment building, activating fire alarms, and leading them to a dumpster where Nikki's bond with the cougar strengthens.
With the pressure mounting from Simon to return Nikki, Loudon navigates a complicated relationship filled with mounting disdain yet undeniable chemistry with her. Their adventure continues as they confront Raoul (Coati Mundi) and his associate Benny (Dennis Burkley), leading to an adrenaline-fueled car chase involving hostages and perilous heights. Ultimately, Raoul divulges the name of the bank that holds the evidence, while Loudon retrieves wedding rings only to find himself in the midst of Wendy's bridal shower, where another zany encounter unfolds.
As the story climaxes, thanks to Nikki's clever maneuvering and her fearless persona, they devise a plan to yield the evidence. After a close encounter with kidnappers at Wendy's celebration, the couple rekindles their connection amid their shared upheaval, leading to a kiss filled with promise for a bright future.
In the denouement, Loudon and Nikki finally track down the safe deposit box. Just as Nikki prepares to board a bus to Philadelphia, she uncovers the explosive evidence linking Simon to Johnny's murder. Realizing the truth, she disrupts Loudon's wedding, prompting him to confess his love for her and abandon his fiancée in dramatic fashion. Ultimately, the story concludes with the two of them boarding a bus destined for Philadelphia, aspiring to start anew and open an animal hospital, with the beloved Murray in tow, symbolizing their adventurous and unconventional love.
