Usagi is still depressed over Mamoru calling off their relationship. Ami and Mako try to cheer her up by taking Usagi to a promise ring workshop.
The Black Moon clan sends down its next operative, Esmeraude, to open the Dark Gate in 20th century Tokyo.
Chibi-Usa falls into a coma after coming down with a mysterious fever. Usagi and the others are at a loss for what to do, when a Sailor Guardian calling herself Sailor Pluto suddenly appears before them.
Ami enters the World Chess Tournament, which is being held at the newly constructed Chess Tower. But Bertheir is also there, forcing Ami to transform and reveal her identity as a Sailor Guardian to the enemy.
Wiseman predicts that Chibi-Usa will appear at Hikawa Shrine. Learning of this, Rubeus orders Koan to go down there and eliminate their target.
Mamoru has a dream in which a mysterious voice warns him that being with Usagi will bring her great misfortune. Meanwhile, Sailor Moon is put into a deep coma after being attacked by a Droid.
A school festival is going to be held at T.A. Girls' Academy, which Rei attends. When Usagi and Ami go to check up on her, they find Rei busy overseeing the setup and events.
Usagi goes to a virtual reality arcade that has just opened up in the Juban District, where she unexpectedly runs into Mamoru, as well as Seijuro and Natsumi.
Usagi, Mako, and Ami see a boy being attacked by one of Ail and An's Cardian monsters. To Mako's surprise, the boy turns out to be her childhood friend Shinozaki.
Two months have passed since the Sailor Guardians defeated the Dark Kingdom. Having lost all memory of being Sailor Moon, Usagi now lives her life as an ordinary girl.
Sailor Moon confronts Queen Beryl's Endymion. She attempts to free Endymion from Queen Beryl's control, but his brainwashing cannot be undone. With the fate of the world hanging in the balance, Sailor Moon is forced to fight the man she loves.
The Sailor Guardians head out into the Arctic Circle. Having anticipated their arrival, Queen Beryl sends the DD Girls, who ambush them. To Sailor Moon's horror, the Sailor Guardians fall one after another as they try to defeat the DD Girls.
Sailor Venus finds the Dark Kingdom's hideout. The Sailor Guardians fall into Kunzite's trap, which hurls them into the past. The girls find themselves in a world called Silver Millennium, where they meet Queen Serenity, the mother from Usagi's past life.
Sailor Moon and the other Sailor Guardians appear to have a falling-out. But it's all part of the plan to locate the enemy's hideout. Also, a nosy journalist named Nana Asahina, who they suspect is a monster, approaches them.
Minako receives a surprise visit from Katarina, an Interpol officer from the UK and Minako's former partner while crime fighting as Sailor V. The two solved many cases together until a tragic incident forced them to go their separate ways.
The Dark Kingdom is trying again to revive the Seven Great Monsters. With five of them already under enemy control, Sailor Mercury and Jupiter scramble to protect Ryo Urawa, while Moon, Mars and Venus stay behind at Hikawa Shrine to protect Grandpa Hino.
Usagi goes on a family vacation to the hot springs, where she is unexpectedly reunited with Mamoru. But due to the Dark Kingdom's brainwashing, Mamoru no longer remembers Usagi or even who he really is.
Olympic figure-skating gold medalists Janelyn & Misha offer to coach groups of five girls. Usagi and her friends decide to investigate. Makoto, a master skater, gracefully glides across the ice and soon begins to receive personal lessons from Misha.
Usagi and her friends go to a ski resort to participate in the Moon Princess Contest, unaware that it's part of Kunzite's plan to eliminate the real Moon Princess. During the ski contest, Usagi and Rei end up falling for the trap.
Usagi decides to take the Princess Seminar course at Rose Mansion to become more princess-like, and the other Sailor Guardians join her. But unbeknownst to them, this seminar is actually a trap set up by the Dark Kingdom to find Sailor Moon.