In the Halo 4 Concept Art trailer, one of the concept art images is the cover of the book Halo Primordium. I’m not sure what Halo Primorduim is about, I haven’t read it. But it’s cover is in the Halo 4 Concept Trailer.
Nevermind the novel won’t be released until 2012, so though it may hold plot hints for Halo 4 we won’t see them for a while…
Actually, I think the cover of Primordium was chosen after the concept art trailer, so that doesn’t necessarily mean anything.
A couple of people have already suggested what that might be, Time Travel. The structure in the background looks like a halo ring, ships are fleeing they appear to be Forerunner. And a group of figures are standing and watching a city burn
Primoridum comes out January just so you know. It’s set on a Halo ring owned by a malevolent, mysterious figure called the Timeless One and it has two humans from Cryptum traversing it. There will be humans on it who are subjugated to horrific experiments. It follows four humans and that is what we see in Primordium’s cover.
I don’t consider it a real hint whatsoever.