Answer:
To teach swindle a lesson for trying to take advantage of him and his best friend.
Step-by-step explanation:
Swindle is a story written by Gordon Korman. It is a children's story about the retrieval of a vintage baseball card. Griffin and his best friend Ben finds a vintage baseball card worth trillions of dollars in an old house but they were stiffed of the money by a swindler called Palomino. So they made plans to retrieve the card when the found out its worth.
Irrespective of the fact that the baseball card cost a fortune, they also wanted to teach Palomino a lesson for swindling them.