Setsuna stays late after school to work with her professor. They have discovered that space is distorting in certain areas of Tokyo, but they cannot figure out why. Reika and Motoki interrupt and ask if Setsuna wants to go out to eat. She apologizes and says she already ate. Motoki comments that "Mako-chan" would love all the plants in Setsuna's office. Reika gets a little jealous that Motoki's talking about another (albeit much younger) girl and drags him out of the office.
Outside, Reika gets Motoki to admit that Setsuna is very pretty. He changes the subject to her studies, and Reika says that Setsuna's professor studies anti-gravity in the United States and that the two are studying the space around the Delta.
Inside the laboratories, Professor Tomoe tries to use a monkey as a vessel. The monkey mutates into a monster, making the experiment a failure. Kaolinite tells him that it's time for "the contact." They both kneel in front of a statue that looks like Hotaru's tear drop pendant. The statue glows and a voice of Master Pharaoh 90 speaks to them. He needs more souls in order to activate the Taioron Crystal. Tomoe explains that they are trying to implant eggs inside the humans in order to begin the utilization, but 90% of those implanted become atavistic. The remaining 10% are perfect enough to fight the Sailor Senshi.
"Sailor Moon..." says Master Pharaoh 90. "She destroyed the daimons in an instant. What is that strong brightness called? Is that Sailor Moon's soul?" The power of her soul is comparable to the power of the Taioron Crystal and the power of the talismans. He orders Kaolinite to find out the secret to Sailor Moon's power and to get the talismans. The voice stops.
Kaolinite calls the fourth Witch, Tellu. "I am Tellu, level 404, and I will obtain the highest quality souls. At the master's request, the souls of the Sailor Senshi. Then I will bring the power that closely resembles the Taioron Crystal!"
Chibi-Usa's teacher gives them back their clay sculptures and tells them to give their work away as a present. Chibi-Usa doesn't know who to give her chalice to. While she's thinking, Kyusuke puts a clay Sailor Moon mug on her desk. He explains to Chibi-Usa and Momo that it's "a sign of friendship" and an apology for being such a bad friend. That gives Chibi-Usa the idea to give her chalice to Hotaru.
Meanwhile, at Mugen Gakuen, Hotaru walks thtough the halls carrying her bag. Two other Mugen girls stop to watch. They wonder if Hotaru is going home early again. Rumor has it that Hotaru is "strange" and possibly ill, that her father is a crazy scientist, and that she has no friends. Hotaru falls to her knees coughing, and she drops her metal pencil case. One of the girls steps on it and mockingly asks Hotaru if she needs help. Hotaru's eyes glow. She picks up the metal pencil case and crushes it in her hand. The girls back away.
Usagi watches the rain fall outside. Makoto asks her if anything is wrong, and she admits that she was wondering why Neptune and Uranus are acting like enemies. Both Makoto and Ami refuse to talk about it.
After school, Makoto goes to the florist shop. She complains to the worker that her plants aren't as healthy as they could be. The strange fluctuating weather is making them droop. The worker tells her about a new kind of plant, a tellurian. They were developed by Mugen and require no water. They are only sold at the school. Makoto thinks about this.
At the Command Center, Ami says that the Death Busters are using Mugen Gakuen as their headquarters. Minako reasons that the head of the school, Professor Tomoe, could be an enemy as well. They all agree that the school and its students seem to be normal most of the time, so the school itself may not be involved with the Death Busters. However, Minako remembers how the Black Moon struck without warning. Luna says that the Delta Zone releases an unusual type of energy.
Usagi reads the file on Professor Tomoe off the computer screen: "'Specialty is genetic engineering. Owner of Mugen Gakuen. Resides at Tomoe Research Labs.'" She gets nervous as she reads that Tomoe has a daughter named Hotaru. Chibi-Usa was going to Hotaru's house that day, and Usagi wonders if it's safe. They leave the Command Center. As they walk towards Usagi's house, Makoto sees a store selling tellurians. Apparently, this business venture by Mugen has branched out into other stores. Makoto buys one out of curiousity.
At home, Usagi sees Chibi-Usa puting on her shoes. Usagi insists on accompanying her to Hotaru's house.
When they get to the labs, Chibi-Usa walks right in. Kaoli-kun stops them, but Hotaru says that they are her guests. Once inside Hotaru's room and drinking tea, Chibi-Usa takes out her clay chalice and gives it to Hotaru. Usagi is surprised that Chibi-Usa isn't going to give the chalice to Mamoru, but Chibi-Usa says that both Usagi and Mamoru helped her make it and it wouldn't be fair.
While Chibi-Usa and Hotaru talk, Usagi excuses herself to go to the bathroom. After she leaves, Hotaru has another fit and starts coughing. She says that when she's near Chibi-Usa's amulet, she feels so much better. Chibi-Usa says that her amulet is called the Ginzuishou. Hotaru's eyes start to glow and she reaches a hand out towards Chibi-Usa's chest. "Ginzuishou...," she says deliberately. [whenever the Ginzuishou is spoken of, it is written using four kanji characters. When Hotaru says it here, she uses the hiragana.]
Chibi-Usa is confused by the change in her friend. Hotaru clamps a hand over her mouth, not believing that she almost snatched the brooch off Chibi-Usa's uniform. Behind the door, Kaoli-kun listens. "The Ginzuishou?"
On her way back from the bathroom, Usagi stops to look at Mugen Gakuen outside the window. She remembers the monster that appeared the day Chibi-Usa met Hotaru. "I wonder what this laboratory is researching." Professor Tomoe comes up behind her and places a hand on her shoulder. Usagi stutters that she got lost looking for Hotaru's room, and Tomoe helps her find it. Usagi collects Chibi-Usa and they leave.
As they walk home, Chibi-Usa sees a woman with dark hair and skin walking in the crowd. She slips away from Usagi.
Minako is amazed by all the plants in Makoto's house. Makoto reads the card that came with the tellurian plant: "'Planet breeding by Teruno Ruru, Mugen Gakuen.'" Both girls start to yawn. They fall asleep. In her dreams, Makoto dreams of a boy she uses to have a crush on. Minako wakes her up in alarm: all the plants except the tellurian have withered. Makoto cuts into the plant and gases seep into the air.
Usagi finds Chibi-Usa and the two look at a map of the Delta. Usagi notices that the Kaiou Zone and the Tenou Zone have the same names as Michiru and Haruka. The girls catch up to Usagi and tell her that the enemies have taken control of Mugen's botanical gardens. At that moment, Haruka and Michiru walk by. Usagi calls out to them, but they run away. Usagi follows.
They lead her to Minato Ward, a division in the Tenou Zone. Apparently, the two live in the Tenou Zone condo tower. Usagi goes to Haruka's apartment and bangs on the door. "Haruka-san? You're a Sailor Senshi like us, but why can't you fight together with us? Why won't you tell us anything?" Haruka listens, but she does not answer.
Giving up, Usagi follows the girls to Mugen's botanical gardens. All the plants are in bloom, making the place look like a jungle. The girls see people collapsed on the floor. The tellurians release a gas into the air to suck away the girls' energy. Tellu arrives and gloats over her flowers.
At KO, Setsuna lies on the floor as a tellurian blooms.
Haruka and Michiru snap to attention. They feel an ally calling out to them.
Setsuna reaches out to the tellurian. "No, I can't die yet. I was born here. The meaning... I was reborn. Meaning... Awaken!" The symbol of the planet Pluto appears on her forehead. The symbols for Neptune and Uranus appear on Michiru and Haruka's foreheads respectively, and the two appear in front of Setsuna.
Mamoru feels that something has just awakened.
The girls transform and attack Tellu. However, Tellu easily blocks Moon Spiral Heart Attack. Sailor Chibi-Moon wishes she could have a weapon too, so she could help Sailor Moon. Luna-P falls from the sky and turns into a heart moon rod with a star at the top. She grabs the rod and aims it at Tellu.
"Pink Sugar Heart Attack!"
Tellu turns into a atavistic monster and charges Chibi-Moon. "Dead Scream!" A ball of energy rips Tellu apart. Everyone turns to see Sailor Pluto standing with Neptune and Uranus.