The little girl aims the pistol at Usagi's forehead. She says that the gun is real and pulls the trigger. Usagi falls backwards, and Mamoru grabs the girl. Roses stick out of the barrel; Mamoru is relieved that it's not a real gun. The girl runs away.
A glowing moon hangs in space. A young man dressed in a white suit and cape stands with a long-haired woman in a short black dress, a man wearing a vest, and a man in a dark suit. He speaks to the latter, addressing him as Safir. This Safir has successfully pinpointed a reaction from the Ginzuishou.
A hooded and cloaked figure appears, holding a crystal ball between his hands. The man in the cape calls him the Wiseman. The Wiseman orders the young people to get "the stone of deception", the Ginzuishou, immediately. They raise their wineglasses in a toast. Each one has an upside-down black crescent moon on his/her forehead.
Four women stand in the shadows. The one with her hair up in two pointed buns steps into the light. She calls the man in white Prince Diamaund. "Near the Ginzuishou, I feel a strong, similar power. The blood of a maiden with the power of fire, like me." She says that Prince Diamaund can count on the four Ayakashi sisters and the Crimson Rubeus, the man in the vest.
Rubeus explains that he will send in recruits as the first phase. "Code: 001. Operation: Recruit."
Usagi and Mamoru search for the little girl. They finally find her in Arisugawa Memorial Park, sitting forlornly on a swing. She is crying for her mother. Mamoru speaks to her, calling her Chibi-Usa. [literally "small bunny". The Usa is an affectionate shortening of Usagi] He offers to take her home. When he touches her hand, Mamoru sees a city of crystal. Chibi-Usa thinks to herself that Mamoru reminds her of her father. Usagi tries to interrogate Chibi-Usa about the Ginzuishou, but the girl refuses to speak to her.
Usagi and Mamoru bring Chibi-Usa to the Tsukino house. Ikuko "catches" them outside, making the two blush. Usagi quickly stammers an introduction. Kenji then joins them and notices that Chibi-Usa's toy looks like Luna. Seizing the opportunity, Chibi-Usa bounces her toy and turns it into a hypnotic umbrella. Luna manages to break the spell's hold on Usagi and Mamoru, but Usagi's parents are manipulated into believing Chibi-Usa is part of the family. Usagi is furious, especially when Chibi-Usa says she's going to watch Usagi for a while.
At dinner, Usagi notices the chain around Chibi-Usa's neck. On it, she carries a large ornate key and a crystal. Luna thinks they should keep an eye on the girl.
The next day, the five girls go to the Crown Fruit Parlor. Usagi is still upset that Chibi-Usa has taken over her family. The girls try to figure out just who the girl is; they suggest "Usagi's love child" and "her long-lost little sister", much to Usagi's annoyance.
Luna and Artemis arrive with new communicator watches and new henshin pens. All the girls crowd around Usagi and swear to protect her.
The boy is Asanuma Ittou, who just happens to be Mamoru's kohai. [a younger student who greatly admires an older student] Makoto wanted to show Asanuma Mamoru's girlfriend. He can't stop saying good things about Mamoru.
Rei looks at her watch and says that she has to go back to T*A to help with the school festival. She's helping with the fortune-telling booth--an easy job for the psychic Sailor Mars.
A blonde girl named Sarashina Kotono is in charge of the festival this year. The festival is held every May and is run in conjunction with Moto Azabu JHS. Thus, Rei bumps into Asanuma on the T*A grounds.
As Kotono leads Rei around, the other girls gossip. They say that Rei has become easier to approach lately, her mother died when she was young, she lives with her maternal grandfather at Hikawa Shrine, and that her father is a politician.
Kotono's very proud of the festival's theme: UFOs. Rei thinks the whole topic is ridiculous, but feigns interest as Kotono rattles on about UFOs being spotted in Tokyo. Rei lets it slip that enemies could be sneaking in, and Kotono thinks she means space invaders like those in movies. She rushes to show Rei the booth on spontaneous combustion. Apparently, there have been an unusual number of spontaneous combustions in Japan recently.
Another T*A girl runs to "Chief" Kotono and tells her that another group is displaying a UFO and spontaneous combustion booth. The group is the supernatural phenomena group, Black Moon. A girl with her hair done up in pointed buns walks in and introduces herself as Kurozuki Cooan, head of Black Moon. At that moment, a UFO appears outside.
That night, the pointy-haired woman accosts a little girl. The woman points her finger at the girl, and the girl bursts into flames.
The next morning, Usagi attempts to give Chibi-Usa the slip so she can go to the May Festival, but Chibi-Usa follows anyway.
At the festival, Cooan is telling fortunes at her booth. Instead of happy fortunes, she is predicting the date of everyone's death. Kotono is called to get the situation under control; she tells Rei to get the nuns before everyone goes into hysterics. However, Rei sees that all the nuns have black crescent moons on their foreheads. Suddenly, one nun bursts into flames. Kotono sees and says that it's spontaneous human combustion.
"Don't tell anyone what we saw until I say it's all right!" Rei yells to Kotono.
Ami shows up, and Rei tells her that new enemies are sneaking in. Ami alerts Usagi on the communicator, while Rei becomes Sailor Mars.
"Mars Star Power, Make Up!"
Using her new attack, Burning Mandala, Sailor Mars attacks Cooan. Cooan drops her guise of a T*A student, and reveals herself as the youngest Ayakashi sister. She shoots flames at Sailor Mars, burning her.
Usagi transforms into Sailor Moon as Chibi-Usa watches in awe and confusion. Sailor Moon uses Tiara Frisbee, but it bounces off Cooan and heads back towards Sailor Moon. Tuxedo Kamen knocks it away with his cane. Sailor Mercury arrives and tries to put out the flames with Shine Aqua Illusion, but nothing works.
When Sailor Moon and Tuxedo Kamen hold hands, a bright light appears. Diamaund watches on a monitor. Rubeus and Chibi-Usa stare. Only Luna knows what the object in the light is. "Queen Selenity's rod!?"
"Moon Princess Halation!"
Cooan is killed as the light passes through her, but Rubeus comes to claim Sailor Mars as his prize. Diamaund tells him to bring Mars back alive. She floats into the sky and disappears.