Season 2 Episode 21 episode 21

Person of Interest Season 2 Episode 21 "Zero Day" Photos

Person of Interest Season 2 Episode 21 "Zero Day" Photos

The enemy of my enemy is...my friend? Finch must go to Root for help when the Stanton virus causes The Machine to malfunction. Plus, Carter gets dangerously close to HR's dealings and Shaw returns, as shown in these spoiler photos for Person of Interest Season 2 Episode 21, "Zero Day," airing Thursday on CBS.