As for something with IV, IV is actually their third album. But the last album they put out is going to be the prequal to them all.
ie
Second Stage Turbine Blade
In Keeping Secrets of Silent Earth 3
:takes deep breath:
Good Apollo Im Burning Star IV Volume One: From Fear Through The Eyes of Madness
The last four songs are just a name, thats all. In Keeping Secrets had 3 songs with the same beginning title, but Second Stage didnt have any that were alike.
The plot of IV is the POV coming from the Writer himself, known as The Writing Writer. Though some of the songs are still from the character POV.