I know it says story trailer, but you know as well as I do how much story comes with Rico - just enough. The rest of Just Cause 4's trailer is reserved for a bunch of flashy explosions but we did learn Rico is in Solis looking for his dad.
Apparently, Rico has gone rogue from the Agency, although they're well aware of his whereabouts. As we've already learned, the protagonist of Just Cause 4 is in South America, in a fictional country of Solis. The fact that it's fictional doesn't take away from its beauty though, as you can see for yourself in between the explosions.
As the story goes, Rico is out to dig out the truth behind the death of his father, much like the Lion King, only with more boom we guess. It seems like finds more than he bargained for though and unfortunately, or quite fortunately if you're a player, the man's plans are under more than one threat throughout the game.
The first one are the baddies of course, the Black Hand militia that reigns supreme in the country. They're led by the "dangerous Gabriela" whose forces seem to be keen on throwing around more explosives than Hollywood's CG departments.
The second one is the weather, which is one of the first things Avalanche back at E3. The company is pretty proud with what they've achieved in their Apex engine, simulating actual crushing force of tornadoes and storms.
In one of the previous trailers, we've learned that one of Just Cause 4's missions has Rico in a vehicle called the storm chaser. This is about the part where we learn that the Black Hand have actually found a way to keep them at bay, like literally, which just makes me laugh for whatever reason. I guess it's just good ol' Just Cause.
Interestingly, even the dev reflected on the fact that Just Cause 4 fans are expecting more of the same, in a sense where the game makes everything possible - if you can think it, you can probably do it. Fair enough, let's go hunt tornadoes then.