The Phantoms break into Madarame's palace to steal his treasure, only to find it is a trap. Revealing the treasure is the original "Sayuri" painted by Yusuke's mother, Madarame is defeated by the Phantoms and admits his crimes in the real world, increasing the thieves' reputation.

Finding himself in an art slump, Yusuke asks Ren to be his bodyguard while he draws inspiration from Mementos, only to receive harsh criticism on his piece. Meanwhile, Akechi asks for Ren's help in finding evidence against an art dealer named Akio Kawanabe, who he believes is into some shady practices. As Yusuke manages to get out of his slump thanks to encouragement from his friends, Ren discovers that it was Kawanabe's assistant committing crimes, allowing Akechi to arrest him. Receiving praise for his new piece, Yusuke declines Kawanabe's funding in order to pursue his own hope.

As a mysterious hacker group known as Medjed issue a public warning to the Phantoms, Ren is contacted by someone known as Alibaba, who threatens to reveal the Phantoms' identities unless they can change the heart of someone named Futaba Sakura. When asked to meet in person, Alibaba suddenly calls off the request and asks the Phantoms not to look into Futaba any further. Learning that Futaba is a relative of Sojiro, who is under pressure from Sae concerning his parental authority of her, the gang, receiving a threat from Medjed that they will attack Japan if their identities are not revealed by 31st July, go to Sojiro's house and come face to face with Futaba.

As the gang try to figure out a way to reach the top floor of Sae's casino Palace, Soujiro, who discovers a calling card in Futaba's room, is under pressure from Futaba's uncle, who is demanding that he pay him money or else give up custody of her. Ren gets Akechi's help to dig up dirt on the uncle, only for him to accuse Ren of pushing him. When government officials come to question Soujiro, Ren and Futaba manage to assure them that Soujiro is a good guardian, after which they come clean to Soujiro about being Phantom Thieves.

The politician who was the mastermind behind all of the cases has been successfully reformed by the Phantom Thieves. However, the public’s reaction was not as expected. In order to eliminate the world’s distortion and enforce the justice he believes in, Ren proceeds towards the final battle along with the Phantom Thieves of Hearts.