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 P1 I realize that I might just as well continue doing some small tweaks to the original adventures in order to make them fit together into a common storyline better. In P1 I did a lot of changes, but I do not expect to have to do as much in P2. The focus in this conversion guide is to introduce Karavakos from the Pyramid of Shadows in the storyline. He will be the final enemy the face rather than Zirithian.
I do not expect as many changes to P2 and P3, as Orcus is quite present in the main story, but I will try to enhance these great adventures to the best of my ability.
Please note that you should read through H3 and P1 Conversion Guides first, as it gives you the full background story to the campaign.