An undercover detective investigating a criminal organisation is tormented by the possibility that her police work led to the fatal shooting of her son.

Jimmy Laszlo learns Grace's true identity; Alec takes revenge against a rival gang; Jimmy strikes a deal with Grace to find the traitor in his organisation.

A firebombing drops the Laszlos between a vengeful Chinese gang and justice-seeking police; Grace finds a link between Jimmy's organisation and the shooting outside Sam's school.

Grace and Jimmy seek the truth behind Charlie's financial dealings; Max agrees to help his father locate the missing cash.

A police insider traces the money found in Charlie's safe; a masked gunman ambushes Grace.

Frustrated by his brother's promotion, Alec starts a fight with Max; Mitch learns that Michael Chen and Sam were killed by the same kind of bullets; Grace and Jimmy look for clues at an abandoned shooting range.