you have been against yourself that is 3 days from the past and is trying to get back and your company has a time traveler, you are an agent that works for the company, and the time travel machine has only a one time use and your company wants to use it but past you is trying to get through the portal before your company, and past you knows that your company is using the time travel machine for evil, right now future / present you and past you are on the top of a building fighting well at least present you is trying to fight, past you is running from your attacks

(you can either be present you or past you, or you can be another you from another time line)