Specific plot details are still under wraps, but it's assumed that a vengeful Black Manta (Yahya Abdul-Mateen II) will be the main villain this time. There's also a good chance that The Trench will feature more prominently, given Wan's fondness for the deep-sea terrors.
The director has also suggested that he'd be returning to his horror roots for Aquaman 2, drawing influence from, of all things, campy '60s Italian horror film Planet of the Vampires.