A possible concise summary is:
Two kids, Junior and Joseph, want to buy some rare and expensive Pokemon cards that feature their favorite character, Poliwrath. They find a blank check in a car they wash and use it to buy the cards for 10 million dollars. The owner of the check, a rich businessman, finds out and demands the cards back. The kids trick him by giving him their old and worthless cards instead. However, they realize that one of the cards they bought is not as valuable as they thought.
Some possible facts extracted from the text are:
1. Joseph and Junior want to buy some first edition, shadowless, PSA 10 Pokemon cards of the Poliwag evolution line.
2. Harry tries to sell them his Charizard and Mewtwo cards, but they are not interested.
3. Junior shows off his Poliwag collection, but Harry tells him they are not shadowless or first edition.
4. Junior and Joseph go to a flea market and find the cards they want, but they cost $30,000.
5. Junior and Joseph start a car wash and steal a blank check from a billionaire's car.
6. They use the check to buy the Pokemon cards from the flea market.
7. The billionaire finds out and confronts them at Junior's house.
8. Junior gives him his old Poliwag cards instead of the ones he bought with the check.
9. Junior realizes that his Politoed card is a PSA 9, not a PSA 10.