A girl drives while texting, and smashes into a stopped car. She gets out to talk to the driver but he flees. She opens the trunk of his car and finds the body of Navy Captain Jeremy Doblin inside.
Bishop reveals that Doblin had three tickets for road rage and was reprimanded for a shady real estate deal.
Abby finds a weird compound in Dobin's blood that she can't identify. Ducky tells her he was in perfect physical health, though he may have been suffering from one or more personality disorders.
Abby identifies one ingredient that was manufactured by a pharmaceutical company. She decides to visit the company to investigate further.
Ducky says that Doblin died from a crushed trachea, and that his colon contained a metallic box containing two jars of botulinum toxin.
Abby meets Dr. Janice Brown at the pharmaceutical company. Brown identifies the compound as a base molecule of a generic antidepressant. The only problem is that the active ingredient is missing.
An alarm goes off at the company. It's a level 4 containment alarm which goes off when the Ebola lab has a leak. As part of the alarm, the entire Ebola wing goes on lockdown. They hear gunfire.
Abby tries to call NCIS but there's no cell service. The landline is down as well.
When they find they have no internet access, Abby checks the computer and discovers that the Ebola leak was a false alarm that was triggered from outside the lab. She activates a video feed and sees the janitor attacking a guard in the hallway.
While going through the crashed car, a phone rings. McGee pulls it out and Gibbs answers it. Whoever is calling wants to meet Doblin to set up a buy. Gibbs decides to set up a surveillance van with the team while he attends the meeting, pretending to be Doblin.
He enters the building, only to find out that Doblin's meeting was to be with some women customers who were looking for cosmetic procedures involving Botox.
McGee determines that Doblin was not a terrorist, and that he likely smuggled the botulinum toxin so that he could manufacture Botox for his patients.
Tony reveals that Doblin was in trouble with a loan shark named Nicky Jones.
Bishop discovers that Doblin had made several calls to the pharmaceutical company.
Abby makes her way to the server room. She hears some men with guns going in the same direction, so she hides in a closet in the room. She brews up a chemical that smells bad, which forces the men to vacate the room. She gets on the computer and manages to place a call to Gibbs, telling him that the place is being robbed.
She then locks out the system so that no one can use it.
One of the men comes back and she hides back in the closet. He tells one of his cohorts that Abby is in the building and needs to be killed.
The NCIS team arrives at the pharmaceutical company. Tony calls the leader of the gunmen, named Travis Cook, who tells him that he needs to get a helicopter to the roof, and that he has hostages.
Gibbs and McGee interview Nicky Jones. He tells them Doblin mentioned there were millions of lives at stake.
Abby escapes the closet through the ventilation vent, and makes her way back to Dr. Brown's office. She sends out orange smoke through to the outside vent, in order to signal distress to Gibbs.
The gunmen use the PA to warn Abby that she is to unlock the system so they can use it. They promise to start killing hostages if she doesn't unlock it within ten minutes.
Abby works with Dr. Brown to create a chemical bomb.
McGee works at the computer to try and unlock the wing. He finally does so just as Abby and Brown are discovered.
They bring the women to the server room. They order Abby to unlock the system. She goes to the computer and instead locks them into the room.
Abby takes out a canister which she identifies as DX7 gas. She tells Cook that if she releases the gas, everyone in the room will be dead within ten seconds.
Cook doesn't believe her, so Abby releases the gas. Everyone becomes unconscious, including Abby.
Gibbs and McGee come around the corner to the outside of the server room. They shoot the man guarding the room and enter the server room.
Gibbs wakes Abby up. She reveals the DX7 wasn't real, and that it was just a knockout gas. She tells Gibbs to arrest Brown because she was working with the bad guys.
Brown tells Bishop that she had hired Cook to steal data to prove that the pharmaceutical company was falsifying safety data to sell generic drugs that didn't work. She says that Doblin was a chemist who figured it out six weeks ago and contacted her research lab to tell her.