Ever since Graham (played by Benedict Cumberbatch an award winning actor) bought the flat cap from the old man he had gotten strange visions, they were small at first, thinking he could see ghost in the room with him but the more he wore the cap the worse the visions got. It started to whisper things to him, make choices for him. His fashion sense was all over the place, he often went out mismatched and people began to take notice. Mismatched outfits turned to strange urges and whispers in his mind. Graham lost his concentration and his work faltered. He was laid off from his position at the computer company he had worked for for years. The thoughts took him over worse and worse everyday until he began to brutally attack people. Attacks became murders and murders would lead to serial killings if Graham’s three best friends (Played by Tom Hiddleston, Chris Pine, Chris Evans) couldn’t stop him.
As mentioned in the movie poster