Here's What You Forgot About House of Cards Season 2

Frank has wormed his way into the Oval Office. He writes President Walker a heartfelt letter (complete with a signed confession implicating himself in Walker's crime), causing Walker to side with Frank against Raymond Tusk. Once Walker takes a presidential pardon off the table for Tusk's involvement in the money laundering scheme, Tusk turns on him and tells the judiciary committee that Walker knew all about the scheme. Walker resigns from the presidency, seeing no way out of impeachment, and Vice President Frank is free to take over.