Pegasus hovers over a lake in the woods, thankful that he's found the Maiden. He can't breathe. A black rose loses its petals.
Mamoru is in the hospital being watched over by two very anxious Usagis. The other girls come flying in to make sure Mamoru is okay. They stop dead in their tracks when they see Usagi and... Black Lady. Usagi explains that their ages were reversed while they were detransforming. The new enemies are undoubtedly behind this. Ami suggests that her mother (a doctor) checks out Usagi and Chibi-Usa after she examines Mamoru.
Usagi and Chibi-Usa are found to be completely healthy and normal. Mamoru, on the other hand, is sent to see a specialist in the hospital. The doctor shows Mamoru an x-ray on his lungs and points out a lung shadow. The doctor wants him to return so he can be examined more closely.
Returning to his hospital room, Mamoru tells everyone that "it's nothing serious." Instead, he focuses all his attention on his two ladies, commenting on how pretty Chibi-Usa's grown up to be.
Chibi-Usa decides to go home alone so she can use Luna-P to trick Ikuko and Kenji into believing she is really Usagi. Usagi goes home with Mamoru.
At the Tsukino house, Chibi-Usa hypnotizes the family. She goes up to Usagi's room and thinks about Mamoru's comment that she is pretty. At that moment, the little bell that Pegasus gave her falls to the floor. Pegasus appears, and he is happy to see that Chibi-Usa has grown. "That body... You've grown! You're beautiful. You are the maiden I've been searching for after all!"
However, Chibi-Usa knows that this body is not her true form. If Pegasus is looking for a grown maiden, then she cannot be the one. Before she can explain that her growth is a result of the enemies' tricks, Pegasus backs away. He can sense the evil spell and says that he knows that her new body is "their" doing. Chibi-Usa asks if he knows the enemies and to reveal his true identity. Pegasus refuses, but asks Chibi-Usa to lend him the power of her beautiful dream. The gilded cage appears again. Pegasus calls her the princess solider who can break the seal on the Kinzuishou before he disappears. Chibi-Usa runs to Mamoru's apartment to tell him that Pegasus appeared again.
At Mamoru's apartment, Usagi has put him into bed and is taking care of him. Mamoru is sorry that he's putting so much stress on her, but Usagi assures him that she enjoys helping him. Actually, Usagi has other ideas in her head since it's been such a long time since they were alone together. She jumps up on the bed and cuddles against his shirt. Mamoru freaks out and backs away nervously. He pats her on the head as Usagi cringes in frustration and reassures her that she'll soon have her body back. To himself, Mamoru says that looking at Usagi like this is like looking at Chibi-Usa.
Annoyed, Usagi thinks that everything has gone wrong. She had to spend her winter and some of her spring taking high school acceptance exams so she couldn't be with Mamoru. Now, when she finally thought she was going to mature into a young woman, she's stuck in a 10-year-old body. Suddenly, she turns to Mamoru and says that she feels their relationship is constantly interrupted by Chibi-Usa. Mamoru resents that and tells Usagi that the little girl is lonely and far from her real home. Usagi winks and says that she'll watch out for Chibi-Usa and will never let her feel lonely. Mamoru smiles at her cuteness, but doubles over in pain. Usagi lays him down. Bitterly, Mamoru says that he feels like he's dragging her down and holding her back because he doesn't have power like her. Usagi dismisses these ideas as Mamoru falls asleep. She lays down in the crook of his arm and kisses him. "My dream, Mamo-chan, is to be with you always." Chibi-Usa stands in the doorway.
Sadly, Chibi-Usa sits on a swing with Diana. "I know," she tells the kitty. "However I love him, Mamo-chan... He's my dad. Usagi is with him." Diana tries to cheer her up by telling her that her new body is pretty and that her parents would be pleased if they could see her, but Chibi-Usa reminds her that it's not her real body. Her dream is to be a real adult, to be a lady, and to meet her own prince.
In Mamoru's dark room, Pegasus leaps out of the mirror. He apologizes to the sleeping Mamoru for not protecting him and for not protecting Elysion. He asks Mamoru to search for the Kinzuishou and he fades away.
At home, Ami pulls up a picture of Juuban on her computer. The Dead Moon Circus has completely taken over the Juuban shopping center. The circus has even managed to put up a force field around the area without anyone noticing; Ami has just found it now with her computer. She remembers that Setsuna once told her to always be prepared for enemies because everyone depends on her intelligence and cool judgement. She needs the self confidence to trust herself as much as the others trust her. Ami wishes Setsuna was with her now, but knows thar she can only rely on herself to solve the mystery of the enemies.
Ami's mother comes home and is suprised that her daughter is still awake since it's 1:00 AM. Ami reassures her mother that she ate dinner and was fine by herself. Her mother says that she is too devoted to her job to be a good mother for Ami. To herself, Ami thinks about her parents. Her father is a Japanese painter who travels around the country and sends her sketches. Her mother is always working at the hospital. Both parents say that Ami works too hard for a kid.
A voice from the other side of a mirror speaks to Zirconia and tells her that the "ones of the White Moon Kingdom" are alive in the modern world. Zirconia addresses the voice as "Nehelenia-sama" and says that she knows how to deal with the Senshi. She summons the Amazoness Quartet and tells them that the people of the Dead Moon were tormented by the Ginzuishou in ancient times. Because of that, the White Moon is their eternal enemy. In order for the Dead Moon to rule the Earth, those of the White Moon must be killed. Fish-Eye steps forward and asks if he can attack first. He looks into a fish-shaped hand mirror and sees the image of Ami at her computer.
"Found you. A manipulator of the flow of water, like me. Carrier of a beautiful dream."
The next morning, Ami calls up Usagi to see if she's still in the wrong body. Of course, she is and she cries for help. Ami hangs up quickly and walks to the circus in the rain. Across from the circus is a tropical fish store that was never there before. Ami goes in and is thrilled by all the colorful fish. Dressed as a shop keeper, Palla-Palla tells Ami that people are attracted to the water as a stress-reliever. Ami asks which fish Palla-Palla recommends, and the girl points out a fish that looks a lot like a fighting fish. Ami buys it and takes it home. Palla-Palla smiles maliciously.
At home, Ami puts the fish into a tank. She wonders if her mother will like it and falls asleep. After a while, Ami opens her eyes and walks into another room. She sees her mother kissing a man. The man looks at her and Ami's mother says that Ami is nothing like her at all. Ami is hurt; as she turns away, she sees her younger self in the mirror chasing after her father. Her father tells her to go away. He says that he is tired of his daughter who does nothing but study.
Sadly, Ami goes up to the mirror. Her father's image fades away, to be replaced by Mamoru, small Usagi, and grown-up Chibi-Usa. The three are laughing and happy. The image of Usagi says that, even though things are not like they should be (ie, Usagi and Chibi-Usa's ages are switched), they three are always happy when they're alone together.
The fish jumps out of the fish tank and becomes Fish-Eye. He creeps up behind Ami and puts his arms around her. He asks her if she's jealous of Mamoru, Usagi, and Chibi-Usa. Still touching the glass, Ami slowly agrees that she's always been so lonely. Fish-Eye tips her chin up and begins to kiss her. Ami breaks away, aware that this is all a trick of the enemies. Her mother and the man develop evil eyes. She runs onto the balcony and tries to call Usagi on her communicator. The lemures attack her and Ami falls backwards into a giant mirror.
Fish-Eye gloats that the lemures have taken over the entire condo. He lets Ami wallow in self doubt inside the mirror. "Yes.... I have no self confidence," Ami mumbles to herself. "I can only depend on others." She closes her eyes and slides into the water in the mirror.
A small voice calls out for "Princess Mercury". Ami opens her eyes and sees a miniture Sailor Mercury flying towards her. The little Sailor Mercury tells her that she is Ami's other self. "You mustn't come under the beck and call of this nightmare created by the enemies," she tells Ami. "Remember your true dream."
Ami remembers that she has many people who love her and who she loves. "I want to love those people more. I want to protect them. For that purpose, I study." Her dream to to become an adult Senshi so she can better protect her friends. She flies out of the water, a glowing heart-shape on her chest. Fish-Eye is shocked and outraged. The shining heart is a new brooch.
"Mercury Crystal Power! Make Up!!"
Ami becomes Super Sailor Mercury. Her new fuku has transparent sleeves and a heart-shaped brooch on the bow. Her choker has a star on the front, and the bow on her skirt is elongated. A harp appears in the air. It speaks to Sailor Mercury: "I am the Mercury Harp." Surprised, Mercury grabs it and strums the strings.
"Mercury Aqua Rapsody!" she yells. The attack shatters the mirror and destroys the mirror. The man with her mother disappears. Usagi and Chibi-Usa rush into the apartment. Taking a chance, they both call out their henshin phrase. They appear as Super Sailor Moon and Super Sailor Chibi-Moon in their proper bodies. They destroy Fish-Eye with Moon Gorgeous Meditation.
From the circus tent, Palla-Palla watches her minion's death. She is more interested in the fact that Usagi and Chibi-Usa managed to overcome her opposite ball.
While Sailor Moon and Sailor Mercury celebrate victory, Chibi-Moon looks at Sailor Moon. She thinks to herself that Sailor Moon is the stronger half of Double Moon. Even though she carries the same Ginzuishou as Sailor Moon, Chibi-Moon feels that she is useless. She raises her bell and summons Pegasus. When Pegasus appears, she blurts out that she is not the maiden he is searching for.
"The maiden I'm searching for," says Pegasus, "carries the beautiful dream. She is protected by the Moon. She is a princess solider."
Sailor Mercury absorbs this information. "The maiden is Sailor Moon? No, Princess Selenity?"
Pegasus asks Sailor Moon if she is Princess Selenity, the maiden he has been searching for. Chibi-Moon closes her eyes as she realizes that Pegasus was not looking for her. She runs away. Sailor Moon calls after her as Pegasus fades away.