Summarize the exciting events at the end of chapter 1 of Percy Jackson lightning thief

Percy goes on a field trip to the Metropolitan Museum of Art. Later on his math teacher Mrs. Dodds pull him away from class and pulls him into a room where she turns into a monster with wings and tries to attack him. Mr. Brunner and Grover come in, Mr. Brunner throws the Percy a pen that changed into a sword. Percy then fights Mrs. Dodds and vanquishes her. When he is done he finds out nobody is there. He goes outside to find out that nobody knows who Mrs. Dobbs is.

Percy introduces himself as a 12 year old who has always been troubled. He goes on a field trip with his class at yancy academy to the metropolitan museum of art where there is an exhibit on ancient greek and Roman history. It is revealed that he is adhd and dyslexic. You also meet several main characters