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!

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.