S04E06 — Target: Hooker

Hooker and Romano are on patrol when their car is hit with a chemical based fire-bomb, which leaves Romano blinded. With Romano in hospital and facing permanent loss of sight, his girlfriend Maggie, a fellow Officer, takes his place as Hooker's partner as they investigate who was behind the attack and why. Unbeknown to them, a recently released convict, who's deceased cell-mate was put away by Hooker, has hired a chemical genius to wipe Hooker out, but the attempts on Hooker's life have deadly consequences for Maggie.