No Deposit, No Return

Tracy and Jay discover Carolyn can't pick them up because she is in Hong Kong. They are to spend the vacation with their Los Angeles billionaire grandfather, J.W. Osborne. Osborne, wary of the children's habitual chaos, vows to keep things orderly and reduce trouble.

On the plane trip, Jay realizes he has mislaid his pet skunk, Duster, causing panic. At the airport, Osborne's loyal butler, Mr. Jamieson, fails to meet them, and the children escape in a taxi.

At Duke and Bert's apartment, Duke initially tries to shake them off, but Tracy's convincing acting persuades him to invite them to stay the night. Osborne spots them leaving in the taxi and follows, yet decides there is no immediate danger and leaves them there.

On Day 2, Tracy hatches a plan to follow Carolyn to Hong Kong. She funds the trip by mailing Osborne a fake ransom note demanding $100,000 by 4:00 pm that day.

Meanwhile, Duke and Bert receive a visit from Big Joe, a local gangster they owe money to, who gives them 72 hours to pay. They reluctantly go along with Tracy's plan but fail to secure any money, and Osborne already suspects the scam.

Tracy makes a bogus kidnapping call that draws Sergeant Turner into the case. Carolyn returns to America, demanding an explanation for how her children disappeared.

Negotiations lead to a dockside exchange arranged to trade money for the children. The police, however, are unaware that Osborne already knows where the kids are.

Duke realizes time is running out and a frantic car chase unfolds along the docks. Carolyn jumps into Duke and Bert's car and learns her children are not in immediate danger.

The chase ends when Detective Longnecker drives the police cruiser off the dock and into the water. The scene erupts into chaos as everyone scrambles to escape.

Tracy and Jay return to Osborne's and hide in the safe when Osborne comes home. Jamieson locks the safe, trapping them inside and heightening the danger.

Duke, Bert, and Carolyn trace the children to the house and confront Jamieson, who claims the children are not inside. A sighting of Duster proves Carolyn's suspicions correct.

With the air running out and no safe combination, Duke uses his safe-cracking skills to open the safe and rescue the children. Sgt. Turner arrives and chooses not to arrest him after witnessing the rescue.

Osborne pays off Duke and Bert's debts and reconciles with his grandchildren. Duke also starts his own garage, and the film ends with a hint of romance between Duke and Carolyn.