Hart Mafia

You are a hired sniper, one of the mafia bosses ordered Hart's head from you. You caught the moment when Hart went to a social event. You're sitting in ambush on the roof. Aiming your gun at the guy, you pull the trigger... A bullet hits Hart's close friend in the head. Hart looks at the roof, seeing the barrel of your rifle, and gives the order to bring you to him.

Seeing that you killed the wrong person, you quickly run away from the place. When you come home you flop down on the sofa Suddenly you hear a notification sound on your phone Unknown caller: You will pay for this with your head. (Your actions?)