From the introduction:
I started out with the ambition of changing the 4th Edition adventure series H1: Keep on the Shadowfell, H2: Thunderspire Labyrinths, and H3: Pyramid of Shadows – as there was very little in the plotline that really tied these adventures together into a full story.
Having just finished up the conversion of P2 I initially did not see any real need to go in and do changes of P3. But after reading some feedback in the forums, I realized that there seemed to be many that was unhappy with the railroading of this adventure. So I decided that I might just as well continue doing some small tweaks to the original adventures in order to make it more open. My focus will be to try to incorporate the city of Gloomwrought in the Shadowfell in the story, as well as more encounters with the Ashen Covenant as well as the followers of the Raven Queen. Hopefully this will lead to a nice transition over to E1 to E3, were I am not expecting any changes at this point.
Please note that you should read through P1 and P2 Conversion Guides first, as it gives you the full background story to the campaign.