The investigation into the killing of the CFO of a baby food company leads Briscoe and Logan directly to the Russian mob and its head, who now goes by the name Steven Green. When they arrest the shooter, ADA Stone isn't above manipulating his situation to get him to testify against Green. However, since no one can be found guilty solely on the testimony of an accomplice to the same crime, he desperately needs another witness. Ann Madsen had business dealings with Green and can testify to having seen the shooter in Green's office the day of the shooting. When it come to actually testifying however she changes her story, obviously in fear of her life. Stone makes it quite clear she will go to jail if she doesn't tell the truth but it leads to tragedy and forces Stone to make a major decision about his future.