 Even mechanically inclined Sister Bertrille can t fix their jalopy of a station wagon, which they need to transport the children to the Feast of St. Anthony Carnival that day. The sisters talk the Reverend Mother into letting them trade in the jalopy and buy another used car with the $800 they have on hand. Sister Bertrille turns to Money Back Hernando, the most notorious used car dealer in San Juan. They strike a deal for a station wagon for $800, plus the trade-in. The new car ends up being a lemon. But luckily, it breaks down next to where Carlos is picnicking with his latest conquest, Diane. He manages to fix it to the best of his ability, but he suggests the sister take the car back to Hernando and get her money back. Money Back is not true to his name, and they negotiate $500 for the buy-back, but she has to come back later for the money. Vehicleless, Sister Bertrille talks Carlos into letting her use his station wagon to drive the children to the carnival. So Sister Bertrille drops Carlos  station wagon off at the convent, and tells the kids to tell the other sisters that she ll be back shortly and will explain the situation, while she heads back into town to pick up the $500. The sisters see the beautiful station wagon and assume it s the one Sister Bertrille bought with the $800. However just as the kids go off, the water heater in the convent falls apart, and they re going to need the $800 back. So Sister Jacqueline takes Carlos  car back to Money Back and sells it to him for $800. Money Back, never one to pass up a good deal however shady, agrees despite not knowing anything about Sister Jacqueline s story but indeed knowing that the car is well worth more than $800. He turns around and lists it for $1,500. So Sister Bertrille needs to go to Carlos to ask for a loan of $1,000, which added to her $500 will allow her to buy his car back. She is reluctant to tell him what she needs the money for, and he explodes when he finds out the reason. However, he comes up with a plan. Sister Bertrille is to go back and buy the old jalopy from Money Back, which she does for $15. Then Carlos goes to Money Back asking to buy the jalopy, implying that a wealthy investor is in town looking for old vehicles such as that and paying a fortune for such. So Carlos and Money Back go to the convent to bid on the jalopy. Money Back eventually buys it back for $3,000, at which time Carlos infers that the investor, while real, is not in town nor might he ever be. Money Back realizes that he has been had at his own game.