The first part is a mostly repeated synth exercise highlighted with some fast keyboard work. John Paul Jones mostly shows off for this first part while Jimmy's double-neck is heard in the back blaring chords. It's quite lively and involves lyrics which would be hard for anyone to remember (no thanks to Plant). This is also the song on In Through The Out Door in which Bonham's drumming is most lively.
The second part is segued in by a mix of fast keyboards and what sounds like a small string arrangement which winds down into an echoing, dark contrast of the first section. The synth is now used for ambiance while Page goes back and forth between a riff that reminds one of twinkling stars and another that is reminiscent of a dark, gaping cave. The drums are used less here and the lyrics are held to the same theme.
The third section winds up with an electronic droning and then bursts into a disco techno-bop. The instruments and vocals are all present and apparent in this section which sounds quite a bit like the first section. Electronic whirring is used to differentiate this section.
Could be used as a reference to a multi-emotional and intricate musi...