Karen scoffs at her little brother Andrew's problem with Luke, a tattling classmate, and Andrew tattles on her for every little thing. One day he lets Midgie out and gets Karen in trouble, but when Karen tells Lisa and Seth that she didn't put Midgie in danger, they don't believe her. As punishment for leaving the front door open too many times, she is not allowed to sing her solo in the jamboree, but on the day before Jamboree Night, Mr. Drucker's lawn is ruined, and he thinks Andrew's toy tractor left tracks on it, but Karen sticks up for her little brother and tells Mr. Drucker that a garbage truck ruined his lawn. Mr. Drucker believes her and apologizes to Andrew. Andrew tells Lisa the truth - he left the door open because he ran back outside to look for his best dinosaur. He apologizes to Karen and she forgives him, and his mother and stepfather punish him for a week. Lisa also apologizes to Karen for not believing her.