When a monster attacked her computer class, Sailor Moon showed up with Luna. It was during the fight that Luna taught Ami to do her first transformation to Sailor Mercury by saying the words "Mercury Power!" That made her the second Sailor Scout to appear. Her powers focusses on controlling the element water and she uses a small virtual computer to analyze enemies and find quick exits.

Everyone was scared of Ami when she first transferred to Serena's school. She was very smart and and the others were jealous. Serena was quick to be friendly though; when she saw Ami standing alone, she went up and talked to her. After becoming a Sailor Scout, Ami found new missions in life besides just school and her medical dreams: to support her new friends, to fight the Negaverse, and to try and teach Serena to become a betterr sudent. Also she lives with her mother,who is divorced.