When Amy first appeared in 'Computer School Blues' everybody thought that she had gotten kicked out of a private school for geniuses but Serena refused to believe that she was a terrible person, and took her to the arcade so that they could play video games (and so that she could see her crush, Andrew). After playing video games for a while Amy realized she was going to be late for her computer class, and rushed away forgetting her disk at the arcade.
Luna told Serena that she was getting strange vibes from Amy and she believed that Amy was from the Negaverse. Luna wanted to look at the disk to see what was on it but Serena didn't want to invade her new friend's privacy, and she refused to believe that Amy was from the Negaverse, and accused Luna of not wanting her to have any friends.
After some arguing Serena agreed to look at the disk to prove her friend wasn't from the Negaverse. When they looked at the disk they found out that it was from the Negaverse, and they rushed over to the computer school to see what was going on. When they arrived they saw a Negaverse monster draining Amy's energy, and Luna noticed the sign of Mercury appearing on Amy's forehead realizing that Amy was the second Sailor Scout, Luna jumped into the air making Sailor Mercury's transformation pen magically appear. She threw the pen towards Amy telling her to hold it in the air and say 'Mercury Power', seeing no other way out Amy did as she was told, and she was transformed into Sailor Mercury.
Amy is the smartest of the inner scouts (the first five). Anytime anything mentally complex presents itself, she rises to the challenge. Rated with an IQ approaching that of a genius, she can generally solve almost any puzzle that the Sailor Scouts finds themselves in. She lives in a mansion with her mother who is a doctor. Amy would like to follow in her mothers footsteps and become a doctor herself one day but for now she's happy being a Sailor Scout. Amy likes Greg, but she claims that she doesn't have time for a boyfriend because of school, and being a Sailor Scout. She also is the most aware of Serena being an emotional teenager; she's not just a superheroine who isn't sensitive to the needs of a young girl. As a Sailor Scout, Amy also fits the description of the idiom "Brainpower over firepower."
