The walls of the different universes are coming down. It is unknown how or why, whether or not it's just a sick trick played upon by angels or demons, or if it has something to do with the current Leviathan situation, or possibly something completely different. But, completely different universes are converging into this point in time, universes that should never have come into contact.
There are different versions of people that already exist, people that should be dead, and most certainly people who have never existed in this timeline. Let's just say, things are completely out of whack, and there's nothing anyone can do, or so they think.
On top of all of this, there are the Leviathans, who are beginning their rise to power. Dick Roman is advancing with his plans, and hunters all over the world are uniting to stop them. Demons are running scared, angels are trying to stay out of it, and unfortunately, Heaven is still in complete disarray.
It's starting to look like the beginning of the end.