Apocalypse details the end of the world as a Thirties Mythos inspired bio-weapon runs out of control. The Rending Box (which comes in its own box and is a beautiful piece of packaging) is the conclusion of a trilogy which has the Investigators delivering a box containing the truth about the universe.
I'm kind of halfway through reading both at the moment and the immediate impact is Graham's beautiful turn of phrase when describing scenes. It's strong prose though also makes me question whether this really works as a scenario rather than a film script. There's an emphasis on story that seems like it might be beautiful rail-roading with little for the players to do but watch a brilliantly described backdrop unfolding.