A materialistic sell-sword is sent to discover what had stopped the flow of magic that runs the city, but when he learns that the source of the power is the harvested souls of his race, he fights the king to liberate his people.

Both extremely helpful pieces of feedback. Thanks guys.

One goal could help/define his weakness.
This could be done with the liberating connection and would be what he,
as a character has to overcome. Which is a result of:
The main goal. Trying to discover and reconnect the power supply.

It sounds like the switch in the middle is a natural progression and not left of field. The only reason to try and include a midpoint is if its a change of character.

Take the recent movie "Side Effects"
http://scriptshadow.net/movie-review-side-effects/

This may be worth the read and help you find the answer your looking for. :D

I'd stick with the second goal. For example, in E.T., Elliot has two goals, "keep my pet alien", then it switches to, "get E.T. home." But generally, it's the "phone home" goal that gets mentioned.