Exactly what happened in her previous existence was finally revealed by Princess Sailor Moon's very own lips. Luna and the senshi cannot easily get over something like this. Meanwhile, having heard from Queen Beryl the truth, Mamoru strengthens his resolve. ""I destroyed the planet...."" With these words, Princess Sailor Moon disappears once again. Inside her heart, she is facing off against ""Usagi"" but... ""The Princess' existence is surely call for calamity to this planet!""

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 back to normal, and tranquility has returned to them all. Arriving at their school is a new, mysterious exchange student, Kuroki Mio. But she is a rival of Aino Minako, and also...?! Having transferred to Juuban Middle school is a new idol, Kuroki Mio. Usagi burns with hostility as the girl is ""Like Aino Minako's rival!"" And finally the two of them enter a volleyball match!

Usagi and Mamoru's relationship has been prohibited since their previous existence, but the two of them- vowing that things ""won't be like last time""- begin their love anew. Given Usagi's excessive zeal, the other senshi cannot bring themselves to strongly oppose them. Yet Sailor Venus, knowing full well the horrors of their relationship, refuses to forgive it. Whilst she considers methods of stopping them, in front of her materializes Zoisite. With the same desire to pull the two of them apart, Zoisite makes Venus a proposition.

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.

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.

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.

Makoto worries about being the only Senshi whose power has not yet been awakened, so she tries whatever she can to make it, while dealing with her feelings and Motoki.

Rei and Minako antagonize over their reactions of their previous life. Rei asserts that Minako- having never awakened her senshi powers- has no qualifications to fight, but that's because she has something in her mind. Meanwhile, coming to the conclusion that no matter how much she hopes it would happen, she'll never have Endymion's heart, Queen Beryl at last comes to the decision to take the Princess's life.

Due to Usagi's tears, Mamoru, who had been lost to the Dark Kingdom, opens his eyes. Simultaneously Luna, Mars, and Jupiter finally learn who the real Princess is. Indeed the Princess of the Moon was Sailor Moon, Tsukino Usagi!! A long, long time ago, in a previous life, Usagi was the princess of the Moon (Serenity) and Mamoru was the prince of the Earth (Endymion) and they were deeply in love. Yet theirs was a forbidden romance. The tragic destruction of both the Moon Kingdom and the Earth came about because of their relationship. But the two of them, deeply tied by fate from their previous lives, have surpassed the boundaries of time and once again met! Soon Mamoru will be leaving to London with Hina, his fiancé. What will become of his future with Usagi from now on?

The spell cast upon Ami started to break by the light of the ginzuishou. But Ami's heart was still troubled, and as though casting off doubts, she hit Sailor Moon with her sword. When she came to, Ami found herself and Usagi in the middle of a forest. No longer cursed, Ami can still remember everything that had happened between her and Usagi through to now. Yet it is too late. Carrying the motionless Usagi, Ami bursts into tears

A life-taking stone has been implanted into Mamoru's body by virtue of Queen Beryl's trap. The more he loves Usagi, the closer he creeps to death. Knowing this, Usagi's anger rises. And with that Usagi changes... Having realized this change, Mamoru is determined to meet Usagi, regardless of the stone's existence within himself. His grace period is until sunset, and if he doesn't return Queen Beryl will take his life.

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

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.

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.

The idol Kuroki Mio, who had transferred to Usagi's class, has skillfully become acquainted with Usagi. Yet there is a rumor spreading about Usagi's classmates that ""Usagi abandoned Mio and fled"" due to what happened that time that Usagi had to go fight the youma and left Mio on her own in a safe place. Thus, Usagi becomes a lone wolf, because she is not able to tell them that she was actually fighting. [Whoever gets the Kodocha reference wins.] Making the appearance that she is Usagi's ally- but in actually attempting to ensnare her- Mio is even going to drag Aino Minako into her trap.

Having seen Makoto become willing to throw her life away to complete her mission, Minako reflects on her own captivity to her past. Meanwhile, Rei, arriving at the Dark Kingdom thanks to Mio, meets with Mamoru! ""Even if it costs me my life, I'll see my mission to the end!""

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.

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 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.

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.

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.

Has Mamoru disappeared in London? Usagi can't take it anymore. And with that, Mio provides her with a heaven-sent opportunity ""You can go to London."" The question is, can Usagi dash to Mamoru's side? In that regard, wanting to go to London, Usagi finds it unbearable. In order to get to England she becomes the attendant of the popular actor Yuuto. But having played the mediator, enabling Usagi to do this, hmm... that Mio must be up to something! As it were, Mamoru flew to London like he was running away from something. But, even if he's in London, fate's not going to leave him alone. As Kunzite noted of the circumstances, ""What kind of meeting is this..."" How will Mamoru respond?