The wonderful cover of "I knew you were trouble" by Lindsey Stirling, Chester See 
and Tyler Ward on Youtube. http://www.youtube.com/watch?v=YgTUFSOuHgQ
The chords are very different to the original song.
But pretty easy.

Verse: G#m B E F#

Chorus: E G#m F# .. (pause) ..   

With capo 2:
Verse: F#m A D E

Chorus: D F#m E