13. Root Cause

Complete story — includes the ending

Reese and Finch take the case of construction manager Scott Powell, who was laid off due to budget cuts advanced by Congressman Michael Delancey, whom Powell is planning to assassinate in revenge. However, as Reese tries to intercept Powell, Finch realizes that he has been framed, and he and Reese are unable to stop the real assassin from killing Delancey. Powell is arrested by the FBI in the face of mounting evidence. Reese helps him escape and enlists Zoe Morgan's help in identifying Delancey's chief of staff Matheson as the real culprit, having hired both an assassin and a hacker to kill Delancey and frame Powell to cover up his own corruption. Finch exonerates Powell after acquiring an incriminating recording between Matheson and the hacker. Matheson is later found dead; the hacker, who goes by alias "Root", admits to having him killed to tie up loose ends, and acknowledges Finch, by name, as a worthy adversary.