Peter Mitchell, played by Tom Selleck, is an aspiring architect sharing a Manhattan penthouse with two unlikely roommates: Jack Holden, portrayed by Ted Danson, a charming actor headed to Turkey for a film shoot, and Michael Kellam, a quirky cartoonist played by Steve Guttenberg. After a raucous housewarming celebration, Jack informs his roommates that a friend has a small package that they'll need to keep safe until his associates can pick it up. Little do they know, their lives are about to take a chaotic turn.
One fateful morning, Peter returns from his jog to find an unexpected surprise: a small basket with an infant girl named Mary nestled inside. Tied to the basket is a note from Sylvia, indicating that Jack is the father. Confused yet determined, Peter and Michael assume this baby is the "package" Jack referred to and decide to look after her—entering a world of uncertainty and responsibility they were never prepared for. As amateur caregivers, they scramble to comprehend the challenges of handling an infant. Peter races off to the store for essentials while Michael valiantly attempts to soothe the inconsolable baby. Every moment becomes a lesson in childcare, as they struggle against diaper changes and endless crying, quickly realizing that their social lives may have to take a back seat.
After a few harrowing days, two questionable men arrive looking for the "package," sending panic through Peter and Michael as they incorrectly assume the men arc after little Mary. In a moment of misjudgment, they hand the baby over, only for Peter to discover that the true package is actually filled with heroin, inadvertently tossed aside on the couch. As chaos erupts, Peter attempts to reclaim Mary from the shady characters, amidst an escalating situation starring a mounted police officer. He soon finds himself enmeshed in a world of crime he never intended to enter.
Under surveillance from both the intimidating drug dealers and the visiting narcotics squad led by Sergeant Melkowitz, Peter attempts to navigate the danger surrounding them. He turns to his girlfriend Rebecca for assistance, only to face rejection. In a wild turn of events, they enlist the help of their building manager, Mrs. Hathaway. However, upon returning home, they discover the apartment ransacked and poor Mary scared, yet unharmed. This atmospheric tension deepens when Jack, who faced an abrupt career change in Turkey, arrives back home and, faced with confused accusations from Peter and Michael, must confront the reality of his irresponsible actions.
The plot thickens as Jack recalls his past rendezvous in Stratford, revealing that he had unknowingly fathered the child after a brief affair with Sylvia. To undo the mess his casual lifestyle has wrought, the trio must devise a rather unconventional plan to release themselves from a web of drug dealings and police intervention. Jack disguises himself as a pregnant woman, hiding Mary beneath his dress, while Peter and Michael embark on a daring mission to drop off the drugs. This leads to a series of nail-biting moments where every second counts, culminating in a mix-up in the elevator that brilliantly traps the drug dealers when they least expect it.
With the help of their wild escapades and a homemade video documenting the encounter, the narcotics squad arrives just in time to apprehend the culprits, clearing Peter, Michael, and Jack from impending legal troubles. However, their relief is short-lived as Sylvia returns to reclaim Mary, escalating emotions as they confront their own attachment to the baby they’ve cared for over the past few months. In a heartwarming conclusion, despite the potential heartbreak of leaving Mary behind, they find a way to welcome Sylvia into their lives. Grateful for the unexpected journey they've experienced together, the trio embraces the new setup, promising to take on the challenges of fatherhood—together.
