It starts with Young Sly Cooper has learned about his Ancestors who are thieves. Then,the Fiendish Five broke into his house to take five parts of the Book called the Thievius Raccoonus and killed Sly's Parents. Sly was placed in the Orphanage where he met Bentley and Murray. After they successfully steal the Children's holiday Cookies from the Selfish director of the Orphanage,They named themselves the Cooper Gang.
Many Years Later,Sly infiltrated the home of Raleigh,one of the Fiendish Five,and retrieve the Page. After Sly defeats him,Raleigh warned him that Clockwerk,their Leader,won't be happy about this. Sly left him to be arrested by Inspector Carmelita Fox,whom Sly is smitten with.
Sly and the gang retrieve two more pages from Muggshot & Mz Ruby leaving them both arrested. Carmelita learned about Sly's Lineage and the taken of the pages. As Sly begun locating the Panda King,He was confronted by Carmelita. Then,The Panda King appeared and attacks them. After Sly defeats him,Carmelita gets captured by Clockwerk.
Sly goes to his lair where Clockwerk reveals that he has been living for thousands of years since his real body was replaced with machinery and held a grudge against the Cooper Clan.
Sly battles with Clockwerk,but gets overpowered. As Clockwerk claimed that he should have killed him when he killed his family,Carmelita shot him the armored Wing,allowing Sly to sever his other wing,causing him to fell in the lava. Clockwerk tried to repair himself,but Sly decapitates him.
Sly finally got the pages back and reclaim his birthright. Back at Police Headquarters,Carmelita has received a Rose from Sly. She looked outside her window to see him as Sly gives her a blow kiss.
Mid-Credits:
Clockwerk's head stood in the lava until he opened one of his eyes.