The story of the various metaseries revolves around the reborn defenders of a kingdom that once spanned the Solar System, and around the evil forces that they battle. The major characters — the Sailor Senshi (literally "Sailor Soldiers"; frequently called "Sailor Scouts" or "Guardians" in many Western versions), teenage girls — can transform into heroines named for the Moon and planets. The use of "Sailor" comes from a style of girls' school uniform popular in Japan, the sērā fuku ("Sailor outfit"), on which Takeuchi modeled the Sailor Senshi's uniforms. The fantasy elements in the series are heavily symbolic and often based on mythology.
Before writing Sailor Moon Takeuchi had written Codename: Sailor V, which centered around just one Sailor Senshi. She devised the idea when she wanted to create a cute series about girls in outer space, and her editor suggested she should put them in sailor fuku. When Sailor V was proposed for adaptation into an anime, the concept was modified by Takeuchi so that Sailor V herself became only one member of a team. The resulting manga series merged elements of the popular magical girl genre and the Super Sentai Series which Takeuchi admired, making Sailor Moon one of the first series ever to combine the two.
The manga resulted in spinoffs into other types of media, including a highly popular anime adaptation, as well as musical theatre productions, video games, and a tokusatsu series. Although most concepts in the many versions overlap, often notable differences occur, and thus continuity between the different formats remains limited.