"Skyfall" was composed in the key of C minor using common time at 76 beats per minute (Adagietto).[16]Adele's vocal range spans over one octave, from the low note of G3 to the high note of C5, on the song.[16]The lyrics closely follow the plot of the film rather than focusing on romanticism.[3][9] According to Epworth, the song is about "death and rebirth", saying "It's like, when the world ends and everything comes down around your ears, if you've got each other's back, you can conquer anything. From death to triumph, that was definitely something we set out to try and capture".[2] The Daily Telegraph writer Neil McCormick described the lyrics as "slightly sinister" and containing references to a number of Bond tropes and motifs.[17]

https://en.wikipedia.org/wiki/Skyfall_(Adele_song)#Composition_and_lyrics