Sailor Moon screams out, calling after Sailor Mars who has vanished in a flash of light, held captive by Crimson Rubeus.

Everyone at the festival notices a bright flash of light in the sky. Lita and Mina come running up to Sailors Moon and Mercury, telling them to un-morph before others come. They do so and then Bunny notices that Rini has been watching them. Bunny angrily questions the mysterious child, coming to the conclusion that Rini is the enemy. She rises her hand to strike the girl, but Luna jumps in front, and Rini runs away. As she leaves, Bunny notices the key and pendant around the girl's neck- that looks like the Silver Imperium Crystal. Luna breaks into Bunny's thoughts, telling her not to scare Rini, or she won't find anything out about her. Bunny is unsettled by the loss of her friend, so quickly taken by the enemy, and she runs back home.

At home, Bunny's mom asks where Rini is, and Bunny tells her Rini is sleeping over at a friend's house. She goes in her room, thinking how she almost hit a little girl.

That night, as rain begins to fall, Luna goes to Darien's apartment and tells him to follow her. She leads him to Rini, who has just been wandering around the city, and he takes Rini back to his place, where she falls asleep quickly. Luna tells Darien she does not think little Rini is the enemy, and Bunny knows that deep inside.

In Rini's dream, she is running, looking for her Mama in a city of crystalline towers, where she hears, "If anything were to happen, you must take action..." Then she is holding a hand (her father?) of a person who is telling her "Sailor Moon is invincible..."

Rini wakes up, rubbing the tears from her eyes. Then, she sees a doll of Tuxedo Mask holding out a rose for her, trying to cheer her up. On Darien's other shoulder rests Luna who introduces herself. He tells Rini it is "called ventriloquism." Rini sits up, telling them she can also "do that" and takes out the cat-eared ball, calling it the Luna P Ball. After bouncing it a couple of times, Luna P starts saying "Small Lady...Small Lady..." Rini tells Darien and Luna that is her other nickname, given by her Mama. Luna P then releases a mist, which Darien notices, but it does not seem to affect him. Then he notices the pendant and key around the little girl's neck. He asks if it is her house-key, but she does not answer clearly. She says the key is important and she cannot go home without it, but divulges no information about her home, saying it is both far away and near by. Then, she changes the subject, asking if Sailor Moon is powerful. Darien replies, "Yes...She's invincible." Rini murmurs then maybe she can help, and falls back to sleep.

Later that day, Darien takes Rini and Luna back to Bunny's house. Bunny is surprised, and Rini goes back into the house. Bunny tells Darien of Rini's pendant, and Darien tells her about the key, telling her Rini is looking for Sailor Moon's help. Darien tells Bunny to "give her a little more time," and then kisses her forehead, trying to cheer her spirits.

The Sailor Scouts all meet in the control room that afternoon. Andy is down there, talking to the girls now that he knows the control room is under the arcade. He wishes them good luck with saving Mars and goes back up to the arcade to work.

Amy plays chess, picking up a piece, thinking about rescuing Mars. Mina is surprised and comments the game seems difficult. Amy explains it is hard, but helps clear her mind. Lita insists the scouts must make their move, investigating Raye's school, thinking she may have found a clue to the Black Moon.

Lita and Amy visit the Supernatural Club, asking about Raye. The member tells them Kotono says nothing is wrong and that Raye has been absent for a couple of days. Then, Asanuma walks in, and Lita and he recognize each other. He tells Lita he was helping with the festival, and then tells about the burned corpse of the sister found at the festival. He asks after Raye, but then Kotono breaks in, telling everyone about the sisters with the black crescent moons on their foreheads. She didn't come forward before because Raye told her not to say anything. Lita assures her Raye will be back at school soon.

Asanuma starts saying he couldn't find the sisters with the black crescents. One of them was at the "Black Moon" fortune-telling booth at the fair, but she is missing as well. Amy asks if anything else was strange, so he tells her about the picture of the UFO from the day of the festival. Then, Asanuma talks about abduction, being kidnapped by aliens. Bunny, Darien and Mina join them, and the scouts head off. Asanuma thinks about how Raye and Darien seem different, like they have a secret.

The next morning, a tired Asanuma walks past Darien on his way into school. Then, he remembers the first time he met Darien. He ran into Darien during the winter, when he came to visit Azabu Junior High High School before the exam. Darien wished Asanuma luck on the exam, shaking his hand, and felt a spark, like a sharing of energy. Then, Asanuma remembers back to a month ago, when Darien got hurt during a soccer game at school, and healed his cut by rubbing his hand over it. He thinks Darien may be an alien, but then changes his mind, thinking it isn't possible.

In the halls on the Black Moon, Prince Diamond walks in, checking the power of the Black Poison Crystal. Sapphire walks up, reporting energy form the Poison Crystal is being used to create droid soldiers to send to Earth. Sapphire tells his brother, Diamond, to much force is being used in regard to capturing Mars, telling him it is dangerous. Diamond snaps at him, and then the moon mark on his forehead becomes a third eye which controls his brother. Crimson Rubeus enters, pledging loyalty to Diamond, and reporting that Sailor Mars is in the Room of Darkness. Diamond calls for Wiseman, who appears and tells Diamond Mars will "have her uses..." Diamond decides not to kill Mars, and Bertie enters, volunteering take care of scouts and capture "Rabbit." This third sister of the Sisters of Deception uses Code 002: Operation Remove.

Mars: "They might already be here..."

Amy is startled when her opponent tells her it's her turn in the chess game. But, she realizes she needs to get going. As she leaves, one of the remaining players tells the other how they heard Amy beat the Junior Master chess player of Japan. As they talk, a faucet bursts, soaking the girl. She runs into Amy on her way out and explains the water pressure is not right in the school. Amy carefully listens to the sound of the water flowing in the pipes and quickly leads maintenance to the bent water pipe in the rear grounds.

Bertie: "To dowse without a pendulum...is the work of the devil."

At the pool, Amy notices Bertie walk past while she swims. She wonder who the depressing woman is, and thinks of Mars. The others at the pool talk about how well Amy swims. Bunny and Molly come up, Molly explaining her mom belongs to the sports club, and Bunny is her guest. Amy tells them her divorced father is member of the club as well. He's an artist who paints Japanese watercolors. He taught her both chess and swimming.

On the television next to the pool, a show comes on introducing the famous dowser, Miss Bertie, whom Amy recognizes. The host of the show explains a dowser looks for items with a pendulum, finding water, gold, even missing children. Besides her dowsing skill, Miss Bertie is in town for the chess tournament, and she issues a challenge to "the girl-genius, Amy."

At the chess tournament, Bertie enters and tells Amy she is interested in her. Amy asks if Bertie can use dowsing to find someone for her, but Bertie surprises her by telling her "You could do it yourself," and refers to her finding the break in the water pipe, calling her Sailor Mercury. Shocked, Amy just stares, and Bertie takes out her pendulum, a piece of Black Poison Crystal.

From the stands, Bunny and Lita cannot tell exactly what is happening, but know something is wrong. Bertie reveals her true form as a Sister of Deception and turns to the crowd, looking for "Rabbit." Amy quickly dashes and flips off the lights to the building. Quickly, the three Sailor Scouts morph and Jupiter launches her "Sparkling Wide Pressure" attack, which Bertie dodges. Then, she dashes out of the building, followed closely by Sailor Moon, Jupiter and Mercury. But, drones in the streets hold back the scouts. "They might already be here." Amy realizes the drones are not human and tells the others to attack as they grab her. Sailor Venus comes in, using her "Venus Love-Me Chain" to knock out many of the drones. Mercury attacks Bertie with "Shine Snow Illusion," but she just laughs at the frozen attack. Bending down, Bertie touches a manhole and a giant bubble of water rises and captures Mercury, choking her. Sailor Moon is angry and uses her "Moon Princess Halation" against Bertie, which destroys the evil Sister. However, Mercury is still caught. Venus tries "Rolling Heart Vibration" but nothing happens.

Crimson Rubeus appears, laughing at the scouts' attempts to break Bertie's "water globe." Sailor Moon turns to him, saying "Moon Princess," but before she can finish her attack, he vanishes with Mercury, leaving with a bright flash of light.

Rini is looking out the window holding the Tuxedo Mask doll. "Sailor Moon...is invincible."