Usagi Tsukino is a 14-year-old junior high student who unexpectedly becomes a heroine after a black cat, Luna, awakens her as Sailor Moon in order to save the world. First, she must save her friend, Naru Osaka, from an evil Youma inhabiting her mother's body.

Ami Mizuno is the highest ranked student in Usagi's class, and Usagi manages to befriend her despite their academic differences. But when Luna suspects that Ami might be Senshi as well, Ami also suspects that as the reason for Usagi's friendship and refuses. When she is attacked by a Youma, Ami realizes how true a friend Usagi is and awakens as Sailor Mercury.

During a string of disappearances of miko priestesses, Usagi runs into one of them, Rei Hino, who is the prime suspect of the missing girls. Usagi defends her reputation, until the two got pulled into another dimension by a Youma, causing Rei to awaken as Sailor Mars.

There is a rumor that the Mystical Silver Crystal will be exhibited at a high-society costume party. Tuxedo Mask decides to look for it, followed by Usagi, but the Dark Kingdom is still one step ahead. Meanwhile, Rei refuses to cooperate with Usagi and Ami, choosing to act on her own.

When Ami feels that her friendships with Usagi and Rei are not genuine, she reads a book on how to be a true friend. This causes friction between her and Usagi, and Ami gets into more trouble when she tries to defeat a Youma without calling for help.

Usagi is saved by a new girl in town from the bullies. When Usagi realizes the girl who saved her is at her school, she befriends her. The new girl, a tomboyish Makoto Kino, seems tough on the outside, but when she lets her guard down for a popular basketball player who turns out to be a Youma in disguise, the vulnerable Makoto must awaken as Sailor Jupiter to defeat him.

Usagi suspects that a Karaoke Crown attendant named Motoki Furuhata is Tuxedo Mask when she discovers a tuxedo jacket with a hole in it like from the battle the night before, and impulsively brings him a gift. Makoto and Rei are invited along with them to an amusement park where they meet two of Motoki's friends - one of which is Mamoru Chiba. Things go well until a Youma attacks Rei, and Usagi unknowingly reveals to Mamoru that she is Sailor Moon.

Rei and Makoto get into a petty argument and when arriving to apologize, Makoto thinks Rei is being kidnapped. Meanwhile, Usagi works very hard for a mascot costume contest for pop idol, Minako Aino, and is attacked by Jadeite at the contest.

When Tuxedo Mask reveals information of the Mystical Silver Crystal to the public to speed up the search for it, the mad rush brings a wealthy businessman to ask for Rei's protection of his gem that seems authentic. Meanwhile, Usagi fights her feelings for Tuxedo Mask after being warned by Sailor V that he is the enemy and gets in big trouble for helping him.

Usagi runs away from home and eventually winds up with Rei at her shrine. There, Luna sees a connection between the legend of Princess Kaguya and the real Moon Kingdom. Meanwhile, Zoisite formulates a plan to destroy all princesses under his hopes of defeating the Princess of the Moon.

Minako is being cared for at the Juban Hospital and Usagi and Makoto abandon the Sailor V search to visit her. Meanwhile, Rei, Ami and Luna go check out a hint on the internet about Sailor V which turns out to be a trap set by Zoicite.

Usagi aids Minako in escaping her manager and spend some quality time together. Later on, Sailor V reveals herself as Sailor Venus, princess of the Moon Kingdom.

Usagi and Mamoru help Motoki find his pet turtle, leading them to a kind hermit with no memories. Meanwhile, the evil Queen Beryl intends to awaken her fourth general, Kunzite.

Usagi faints as Kunzite's spell to transform her into a Youma comes back into affect. While Makoto and Rei run off to find Kunzite, Ami does her best to help Usagi fight back.

Usagi goes on a mission to recover Minako's stolen jewels. Meanwhile, Ami has tension with Naru but won't tell the others why.

Ami is jealous of Naru's relationship with Usagi. Meanwhile, Youma are causing people to disappear in order to steal their energy.

Usagi is overwhelmed by her feelings for Mamoru and decides to get over him by making a scarf for Tuxedo Mask. Meanwhile, Rei visits her mother's grave and runs into Minako... who she sees transform into Sailor Venus!

Rei and Minako are butting heads with each other. Meanwhile, Usagi is still distraught over Mamoru, who is about to get caught up in a youma trap with his girlfriend.

It's Valentine's Day and Usagi is babysitting a young girl with a similar romantic crisis. The two are able to use their own situations to help give the other more courage.

Hikari asks Usagi to go on a double date with Daichi and Mamoru, but they are followed by Minako and Usagi soon learns that Mamoru and Hina are engaged. Meanwhile, Rei goes off on her own and Kunzite plots to capture his own Sailor Senshi.

Usagi takes a sick day following the situation with Mamoru, but Ami is also noticeably missing from school. Makoto finds her curled up in bed and cares for her before Ami makes an odd request to go to an amusement park where she passes out! Ami is rushed to the hospital where she later escapes and makes her way to Kunzite for a startling discovery.

After the team's introduction to Dark Mercury, Usagi finds that Ami has turned their class against her. Later, Mars and Jupiter battle a Youma while Ami challenges Sailor Moon to a fight.

Rei runs into Minako during one of her monthly visits to the hospital and gets forced into putting on a performance for sick children. Now it's Usagi to the rescue, who is there to help Rei in her time of need.

Even though Usagi decided to stop thinking about Mamoru, she runs into him in the street. After learning that he's leaving to study abroad Usagi is overjoyed, but when Hina reveals that he'd possibly been attacked by someone named Kunzite, Usagi leaps into action and runs to his rescue.

After Usagi learns that Mamoru is Tuxedo Mask, Hina realizes his feelings might belong to another. Meanwhile, Kunzite has a hunch that Sailor Venus is not the real princess.