No intros showing in my call of duty mw3

Hi guys

I bought an (Unoriginal) call of duty mw3 and installed it. The game works great, but the problem is that when playing no intros between missions appear. I mean whenever I finish a mission, it loads and then takes me to the next mission immediately.

How can I fix this? Is there a way I can download the files of the intros and place them in the directory of the game ?

Thanks.