The trailer for Focus immediately made me think of Matt Damon's pickpocket character in the Ocean's 11 movies. Will Smith's character here is very similar, although more of a con man, and the moral of this film is that you shouldn't always believe what you think is real.
Nicky (Will Smith) is the ultimate con man; he and his team can pull in over a million dollars when a major event is going on. He meets Jess Barrett (Margot Robbie) in a restaurant, and she tries to pull a small-time con on him - once they're upstairs in a hotel room, her "husband" bursts in, starts to get upset, and brandishes a gun at Nicky. Nicky knows it's a con, though, and is pretty calm; Jess is in awe and asks him to teach her the tricks of the trade. He takes her with him to New Orleans, during Super Bowl week, and by the end of the week, they and the rest of Nicky's team leave rich; however, Jess isn't entirely fulfilled with how she and Nicky leave their relationship. He next runs into her three years later, and the game is still afoot - he's there for a con, but she doesn't know that, and what happens during the rest of the movie will make you question everything you believe to be true.