Louis already knows Mike’s secret but it took all of the last six episodes for Mike to build his trust and get everyone involved and working as a cohesive legal team. The momentum will likely carry through to the fifth season.
Harvey and Donna still have some loose ends to attend to that were highlighted during the past season and those can become interesting plotlines too for Season 5.
Still, the premise of “Suits” is about unmasking Mike Ross for who he really is. He is like someone who has a big bullseye on his back and the show revolves around how he always avoids getting caught.
Sure Mike has been caught many times in the past four seasons. But he always finds a way to extricate himself out of the mess and be back on track. Nearly everyone in the main cast of characters already know the secret of Mike, including Rachel, but instead of them going against him, they all supported him and solidified his reputation.
So it is possible that those eyeing to uncover Mike would most likely come from outside of the top New York City law firm but they have to go through the three name lawyers to do that so that really makes “Suits” quite captivating to fans and viewers.