Tonight's episode "Northwest Passage" was scored by Pearl Jam guitarist Mike McCready. Originally, the plan was to use the Pearl Jam song "Just Breathe", but according to Rolling Stone Magazine:

After some back and forth they wound up with something even better: guitarist Mike McCready offered to compose the score for the entire episode.  

 This is the first television score for McCready:

 "It's a completely different kind of songwriting than what I'm used to," he says. "Chris Chilton, who writes the music, gave me some ideas and I transcribed them on guitar. They told me they wanted some sort of Northwest, dark-type feelings. It's a very dark show, so I played a darker kind of guitar tone and even stuff that doesn't sound like guitar, and a little bit of piano."