On Quantico Season 3 Episode 2, Owen's black ops team gets their first case. A deadly strain of tuberculosis is released at a restaurant, infecting and killing most of the diners.
Alex brings aboard two newbies who are still in Quantico: Celine Fox and Jagdeep "Deep" Patel.
There's one girl, Gracie, who appears to be immune. Harry, Alex, and newbie Deep go with Gracie to run tests. On their way, however, they are ambushed.
A militia is behind the attack, so Ryan goes undercover to try to learn more about the militia's plans, where they got the deadly TB strain, and if they have any more vials. Owen introduces Ryan to FBI agent Mike McQuigg, who is already undercover with the militia.
Alex chooses to release Gracie from her quarantine, infecting her, Deep, and Harry, in order to get to safety. They manage to get to a cabin, but it doesn't take long for them to start showing symptoms.
Everyone back at black ops headquarters manages to find the pharmaceutical company who gave the militia the deadly TB strain, and with Ryan's help, they are able to definitively link the two together.
When Ryan, Mike, and Owen bust the militia, they find the remainder of the vials containing the TB strain, but there is one vial missing. Unfortunately, they aren't able to stop the attack, but they are able to quarantine the soup kitchen that's hit.
After surviving a shootout and patching a wounded Gracie up at a vet's office, Alex and company are safe too. Alex, Harry, and Deep all recover from their exposure to the TB strain.