Wiseman plans to use Wicked Lady to open the Dark Gate to send dark energy through her and destroy the world. Sailor Moon and Tuxedo Mask try to convince her to turn good again, and at times it seems to work, but then she turns evil again because of Wiseman. At one point, she even tries to strike down Tuxedo Mask, but when he collapses in Sailor Moon's arms and she checks to see if he's alright, this gives pause to Wicked Lady continuing her attack, startled by how Sailor Moon cares so much for Tuxedo Mask. When it seemed Wicked Lady would stay evil forever, Sailor Moon uses the Imperium Silver Crystal to transform into Princess Serena, at the same time resembling Neo Queen Serenity, and convinces Wicked Lady that she loves her, and eventually she is turned back into Rini, breaking Wiseman's spell over her.
Wiseman appears and, despite his fury over Rini being turned back to the good side, says that the Dark Gate has been opened, and the world will be destroyed. He also reveals that he is the Doom Phantom, and says he will vaporize everyone. Sailor Moon transforms into Princess Serena again, and uses the Imperium Silver Crystal to shoot an energy wave at Wiseman as he uses his crystal ball, powered by the Dark Crystal, to shoot a dark energy beam at her, and they enter a beam struggle. With the Dark Gate open, the power of the Silver Crystal is nothing compared to the Dark Crystal.
As Rini confesses that this is all her fault and accepts that she has brought about all this because of her taking the Imperium Silver Crystal of the future, the Silver Crystal of the future appears in front of Rini, who realizes that it went inside her when she lost it. Just as Wiseman is about to destroy Serena, Rini uses the crystal to transform into Princess Rini. Serena and Rini are powered up by Sailor Mercury, Sailor Mars, Sailor Jupiter, and Sailor Venus, and use the two Silver Crystals to unleash an energy explosion, destroying Wiseman and decimating the core of the Dark Crystal.
The Dark Crystal dissolves into nothingness and the Dark Gate is closed forever. Rini returns to the future, which is now back to normal, as are Neo Queen Serenity and King Endymion, whom Rini reunites with, along with the four Sailor Scouts.
- Final appearance of Wiseman / the Doom Phantom.
- The song that plays during the final battle is "The Power of Love"