It's from the song Anastasia. If you have guitar pro, you can get the tabs there. Or you can try to read the regular tabs here:

http://www.911tabs.com/link/?7923555

Song (Part you were referring to is at 5:20 I believe):
https://www.youtube.com/watch?v=G49s6t6Bj5E

It's basically just trills on the E string and sliding down the neck with basic patterns. The only difficult part about it is getting speed and consistency down, but there's nothing overly complex going on here.