Once Serena gets to school, Melvin tells her that Princess Diamond is in town and is throwing a party, and she has something called an Imperial Crystal. Luna suspects that she is the Moon Princess. So does Queen Beryl, who is now searching for the long-lost Imperium Silver Crystal, which they need to release the Negaforce. Despite his previous failures, Beryl sends Neflite after her instead of Zoycite. Zoycite goes to the fourth commander, Malachite, who tells her that she will get her chance and he doubts Neflite will succeed.
Tuxedo Mask is having visions of a princess telling him to find the silver crystal.
When Serena arrives at the party, she sees that everyone is wearing masks that resemble that of Tuxedo Mask. Neflite dances with Molly. A woman spills a glass of wine on Serena, and she walks off to clean up, and is seen by Tuxedo Mask, who thinks she is the girl from his dream.
Neflite takes Molly onto the balcony where he implants a phantom called Soul Shadow inside her, possessing her.
Tuxedo Mask dances with Serena. She somehow gets the feeling that they have danced before.
Molly enters Princess Diamond's room. Princess Diamond hates talking in front of people, and has glasses that resemble Melvin's. Soul Shadow transfers from Molly to Princess Diamond, who runs off with the Imperium Crystal. Princess Diamond tries to throw the crystal over the balcony to Neflite, but Serena stops her and is thrown over the edge, but is saved by Tuxedo Mask. Princess Diamond tries to throw him off, but Luna attacks her. Neflite tries to attack him, but Sailor Mars arrives with Sailor Mercury and uses Mars Fire Ignite on him. Serena transforms into Sailor Moon.
Princess Diamond knocks out everyone, but the three Sailor Scouts appear. They go outside, where Sailor Mars throws a scroll attack, Mars Fireball Charge, at Princess Diamond, causing Soul Shadow to appear, with Neflite's face. He blasts them, but Sailor Mercury uses Mercury Bubbles Blast to stop the attack, and Sailor Moon destroys Soul Shadow with Moon Tiara Magic.
Luna asks Princess Diamond if she is the Moon Princess, but her shock at a talking cat proves that she isn't. Everyone inside wakes up, but unfortunately, Mr. Tsukino's camera (which he was using to take pictures for Serena) is broken. Princess Diamond presents the Imperium Crystal, which Neflite now knows is not the silver crystal.
In the original Japanese, both Serena and Tuxedo Mask ended up falling from the balcony, but Luna throws an umbrella to them, which they use at a parachute to land safely. In the dub, that scene was removed and editors made it seem like Serena was rescued by Tuxedo Mask instead.
- This marks the beginning of the search for the Imperium Silver Crystal
- First and last appearance of Soul Shadow
- First appearance of Malachite