An elite task force tackles New York City's most complex and demanding cases.

A community is shattered and everyone's faith in humanity is put to the test when a nun is murdered; secrets, inner demons and dark memories begin to crack the surface of the smooth running SIU.

A new detective joins the team after lending a hand on a previous case; the mayor's son is missing and SIU is brought in to solve the case quietly and quickly.

The SIU team is called in when a former Russian diplomat ends up dead, and the team members suddenly find themselves pawns in an international conspiracy involving money laundering, CIA spooks and former KGB hit men.

A new designer drug is killing kids and the team turns the city upside down looking for the dealer; lives are torn apart as the head of the Albanian mob finally discovers who took his money.

Everything comes to a head as Argon closes in on Jimmy and Darius; Jimmy starts to crack as the world closes in around him.