It's a loose tie to Dawn of the Artifacts. Artifacts Unbound follows those up, and will have some more direct information about the Seattle Artifact Rush in it.
At it's core, the "Artifact Rush" is basically a publicity stunt, of sorts. A number of parties have realized that there are items that have power that predate the 6th World, and started hunting for them. The Atlantean and Draco Foundations are two of the main groups interested in these ancient artifacts, and they've set up their Seattle offices as a repository and research depot for these artifacts, so they're shipping any that they find into Seattle.
Basically, the two entities are fighting for resources... Artifacts themselves, as well as researchers, information, etc.
The artifacts themselves are generally McGuffins. They represent knowledge more than direct power usually, so they aren't things that players will be able to pick up and use, normally. They're not D&D magical items. Sometimes they just represent something unusual. Sometimes they're a completely unknown magic type. Sometimes a specific ritual or set of circumstances are required to use them, and only for specific purposes.
Bull