Not this "it's a concept album about [insert random topic you'd like DT to write about]" again please
Concept album about writing concept albums.
If you think about it, Black Clouds and Silver Linings is sort of a concept album about the band itself. It starts with JP getting into a car accident. After he gets out of the hospital, he finds himself facing writer's block. Meanwhile, MP feels like he finally put an end to his addiction, then having to face the death of his father. Then back to JP, who's still stuck with writer's block, and decides to take a vacation in Tuscany, where he meets the Count, who gives him a great story to write about, thus completing his story arc.
I don't know where the Freemasons come in. Maybe the doctor who treated JP after the car accident was one.