I know how the 7th HP book ends?

Harry sneaks up behind Voldemort and shoots him in the skull. He is then arrested for first degree murder. Ginny takes over Voldemort's place as Dark Lord. Ginny then promptly feeds Hermione to the giant squid and turns Dumbledore into an Inferi. Ron goes along with his sister's plans, and is given the Hogwarts castle, which he turns into an apartment block.