The Lightning Thief
How we cite our quotes:
I asked Grover where Mrs. Dobbs was.
He said, "Who?"
But he paused first, and he wouldn't look at me, so I thought he was messing with me. (1.155-157)
Grover has a hard time lying; it doesn't come easily to him. But he knows the importance of erasing Percy's memory of Mrs. Dodds.
"There was no way I was going to remember the difference between Chiron and Charon, or Polydictes and Polydeuces." (2.18)
Percy has a difficult time memorizing names and studying names and facts. Maybe that's his dyslexia and his attention deficit disorder kicking in.
"Thank you, Percy," my mom said. "Once we get to Montauk, we'll talk more about …whatever you've forgotten to tell me, okay?" (3.74)
Percy's memory is being manipulated by Chiron, Grover, and Sally Jackson, who are all trying to protect him from knowing that he's a demi-god.