In this scene, Percy is confronted by Mrs. Dodds. She turns into a sort of creature that looks sort of like a gargoyle. Mr. Brunner throws a pen over at him and says "En garde, Mr. Jackson! The pen is mightier than the sword!" As he said the sword, the pen turned into a sword. Percy defeated Mrs. Dodds and she turned into some type of yellow dust.
Visit to the Underworld
Sally, Percy's mom, had confronted him about school that day. Percy told her about Mrs. Dodds and then grover arrived in his satyr form. They quickly tried driving to the camp. However, they were attacked by a minotaur. The minotaur strangled his mom and she died, or so Percy thought.
Returning the Master Bolt
Percy arrived at Camp Half-Blood. The environment was completely new to him, so he was very confused when he first arrived. Mr. Brunner, also known as Chiron, helped him understand why he was there. He explained everything, including that he had a quest to do with the stolen master bolt.
Reunited With Sally
During Percy's quest, they had to visit the Underworld. Percy, Grover, and Annabeth initially thought Hades had stolen the master bolt. However, they were proven wrong when Percy found out it was in his backpack. Percy also gave Hades back the helm of darkness.
Percy finally met his father, Poseidon, and his uncle, Zeus. He went to return the master bolt to Zeus.
At the end of the book, Percy's mom comes back. This happened because since Percy returned the helm of darkness back to Hades, he did Percy the favor of releasing Sally from the underworld.