Watch the Melodic Harmonics online guitar lesson by Jennifer Batten from Rock Sauce For Lead Guitar
The melody in this song is comprised of only natural harmonics. You can't or can't easily get every note of a diatonic scale with natural harmonics in every key. Tunes in the key of E minor or B minor have some of the most easily available harmonic scale tones. Playing this melody will get you used to the idea of using natural harmonics in a more thoughtful way than just sprinkling a few of them into improv from time to time.