In issue #3 we are told of Parallax's take over of Hal Jordan's body giving us a quick summary of events that transpired in previous issues of the Green Lantern. We also learn that The Spectrum may have an ulterior motive for merging with Hal Jordan and Parallax.
This is a powerful and necessary issue to understand the emergence of Parallax, the motivation of Hal Jordan, and the return of Sinestro from death. The key is the Yellow Power of Parallax.