Hate to be a jerk about it, but you may as well ask where the light goes when you switch off the light bulb. This line of spiritual thinking continues to deny the existence of death by engaging with it in childish ways.
The answer of course is nowhere. The light is produced by the electricity and the filament and the vacuum of the bulb, and the glass. It has no separate existence; no split nature.
The soul is how we describe the performance of the body, it is not a thing in and of itself. Driving is the soul of the car; Aces and eights are the soul of Black Jack. When you junk the car noone ask where the driving went.