One of the most confusing moments of the recent Game of Thrones season finale is when Stannis Baratheon shows up with an army to fight the wildings. It's a memorable scene, but unless you've read the books, you may have been confused as to why Stannis leaves his post to get involved in this conflict. In a season four extra from HBO, author George R.R. Martin himself explains Stannis's motivations in the finale. Watch and learn!