There is a melody that Chris plays and it goes like this:
C chord formation, pluck A string 3rd fret, strum C chord, 0h2 D string, strum, 0h2 G 
string, strum, 0h1 B string




C      F    C
If you called on me
     G        Am       F                      G
I'll take the journey, to bring my love... to you (melody)
C       F       C
If you need me to stay.
 G              Am          F             C          G
I'll sink the ship and build our house out of its bones. (melody)
Am                                                     F
Until I saw your face I never knew a place I could call home
C
Spend some time
G
All alone
Em              Am
But now I got you
F               G
and you got me (melody)
*knock guitar twice*
Knockin at your door

Melody x4

C        F         C
If you love me back
G                Am   F           C       G
I'll love you more than you have ever known (melody)
C     F        C    G    Am     F  
   C        G
If you love me so.  Then I will go anywhere... for you. (melody)
Am                                                      F
Until I saw your face I never knew a place I could call home
C
Spend some time
G
All alone
Em             Am
But now I got you
F           G
and you got me (melody)
*knock guitar twice*

Knockin at your door

Melody x3