Beverly Hills fashion tycoon Sam Stone (Sam) carries a profound animosity towards his wife, Barbara, having tied the knot with her purely for her wealth. His plot to dispose of her and seize her $15 million estate crumbles when he returns home only to discover her missing. Instead, he finds a baffling note from her kidnapper, who demands a substantial ransom for her safe return. What Sam doesn't realize is that his mistress, Carol, has her own plans: she sends their lover, Earl, to gather proof of Sam's sinister intentions. However, Earl inadvertently records a compromising interaction between a couple at a cliffside, mistaking the woman's screams for Barbara's demise.
Meanwhile, Barbara is confined in the basement of Ken and Sandy Kessler, a struggling couple seeking retribution from Sam for stealing their savings and fashion ideas. Despite their efforts to intimidate her, Barbara stands her ground, eventually earning Sandy's sympathy as she begins to question their actions.
Carol's misguided attempt to trap Sam by sending a tape of Earl’s blunder backfires when Sam misinterprets it as a birthday gift, replying with a lewd message that sends Carol and Earl into hiding. Unbeknownst to them, their interference has triggered a series of events leading to Sam's undoing.
As Barbara starts to reshape her appearance through televised workout programs, she finds comfort in Sandy's fashion designs tailored for her new figure. On the other hand, Ken's desperation grows as he continuously drops his ransom demands, ultimately accepting a meager $10,000, which Sam dismisses outright.
Carol's efforts to smear Sam by forwarding another incriminating tape to the police chief, Henry Benton, backfire spectacularly when it’s revealed that he plays an unsuspecting role in the footage. This revelation sets off a chain reaction culminating in Sam's arrest after the authorities seize chloroform and scandalous photos from his affair with Carol.
As Ken's moral compass reawakens, he heads home to grab Sandy and swiftly escape to Mexico, only to find that Sandy has freed Barbara. The women form an unexpected partnership, planning to leverage Sandy’s fashion empire. Their plans, however, are interrupted by the nefarious Bedroom Killer, who confronts them as Barbara reenters the scene. A fierce confrontation ensues, culminating in the killer's unexpected downfall after crashing down the basement stairs.
Driven by vengeance and empowered by newfound resolve, Barbara teams up with Ken and Sandy to get back at Sam, their adversary. Together, they devise a plan to extort a fortune of $2.2 million from him as payback for his betrayal. After his release from captivity, Sam hesitantly collects the ransom money, eager to clear his name regarding Barbara's disappearance.
Meanwhile, Carol finally watches the erroneous tape and realizes Earl's blunder prompting her to reunite with Sam as they prepare for the ransom exchange. Their plan faces a setback when Earl ambushes Sam and a disguised Ken, leading to a tense confrontation that results in Earl’s capture.
With the law closing in, Ken issues a menacing ultimatum: Barbara will face dire consequences if the authorities intervene, spurring his escape with a police convoy in pursuit. Cornered and desperate, Ken leaps off the Santa Monica Pier, seemingly meeting his end in the water. The police later recover the Body of the Bedroom Killer, mistaken for Ken, yet the ransom remains a mystery.
Despite Sam's belief that Barbara must have perished in the chaos, she reappears on the pier, identifying the real killer and sending him tumbling into the ocean. In a surprising twist, Ken resurfaces from the depths of the sea in scuba gear, triumphantly holding the briefcase full of cash, celebrating his victory alongside Barbara and Sandy.
