What the title says. Hermione, a.k.a. "Sakuya", must become the Card Captor because Sakura decided to be a selfish bitch and release all the Cards she sealed. "Sakuya" has a family reminiscient of the Weasleys in size, but without anywhere near as much attention given to characterization. She ends up sleeping with Harry, except his name is now Azrael, because everyone thought he should have a Japanese name. And Eriol becomes Aaron, and then thankfully, the fic ends. Hooray for badficcer's laziness.
She reminds me of Ariana Black in some ways. She's Draco's sister, a supposed Squib, has a nauseating nickname, comes with her very own Scary Sue, and shunts all the canon characters to the side. She's also the Heir of all the Founders, and gathers the individual Heirs to her so that they can capture the Hogwarts Cards together. Starting with the mini-Founders. The last chapters go all crack!crossover-y, then it trails off.
This is one of my most hated Sues. It's not just that she's Draco's cousin from the U.S., or that she's a very blatant self-insert, or her oft-described looks. It's that she takes over the plotlines of both CCS and PS/SS and warps them to center around herself, changes huge plot points (WTF is up with Fujitaka?!), makes up flaws like "short temper" and drops them a few paragraphs later, and gives herself more angst than Harry. There's a link to the fic in the comments; the author also has a short-lived sequel. The sequel is a classic HP/CCS badfic crossover with a Sue thrown in, while the original will make you wonder why she thought that canon needed her revisions.