The episode opens with Peterson overseeing the construction of his nuclear warhead. The impending test is scheduled for the next day, and once it's initiated, the entire world will witness Iran's power. Larijani, of course, is elated and receives a round of applause. He then promises a final test, but Larijani wants to bypass all that and move the bomb immediately.
The warhead is now moving to Lavasan, situated on the outskirts of Tehran. When Peterson arrives, he calls his daughter, but the Mossad are listening in. The message isn't for Jenn—it's for Tamar. Peterson recites the words they spoke to each other in the safehouse several episodes back. Tamar picks up on this immediately and hopes to see him again for their sakes. He asks her to pick him up, and Tamar goes for it
Mossad is aware of how far along the nuclear warhead is and intends to intercept it before the big test. They're currently surveillanceing every point of entry, waiting for movement to strike. Once they're at ground level, they'll neutralize it with a drone en route to the test site. However, this could cause significant collateral damage and even set off the blast inside the city if they're not careful. Yulia, though, is ruthless and prepared to take that risk.
Ramin and Tamar head straight for the villa where Peterson is being moved out. Tamar sends a text to the guy driving, telling him to duck, before firing through the car and killing the driver and passenger outright. Although the car crashes, Peterson is still alive.
Peterson explains that they're moving the warhead but need to be quick. He's actually primed and armed the bomb to detonate at 12 noon that day—less than two hours away. Eric Peterson has spent the last 2.5 years making the Iranians believe he was giving them the bomb. This was only so he could destroy it from the inside, wreck their entire program for good, and cripple them. The bomb was supposed to explode at the lab, but the timeline changes have now jeopardized everything.
The depth of the tunnels and the radiation would have been contained to that area, essentially crippling Iran completely. However, there's no choice but to evacuate the world, which would expose them for the liars they are and show the blood on their hands.
To make matters worse, the Iranians are playing this smartly. Instead of leaving the lab with just one van, they have six, all lead-lined and with an escort. This is a way of throwing Mossad off their tail. The only solution is to hack the traffic and try to stop the vans from leaving.
This puts Tamar in a difficult position. Mossad wants to destroy the bomb outright, while the Iranians obviously want to test their weapon. Peterson, Tamar, and Ramin must figure out the best course of action.
Faraz is the key to everything though, and Tamar calls him now, telling him he has to leave the building in 3 minutes without attracting any attention or he'll never see Nahid again. Faraz complies, but on his way out, Behrouz notices the suspicious car that pulls up and takes him away.
Tamar and Ramin are here, along with Peterson, and the only solution to stop the city from blowing sky-high is to let Peterson get there and manually disarm the bomb. Time is of the essence, and they're running out of it.
One of the trucks heads into a disused tunnel, followed closely by Tamar and the others. There's no reception in there, so Larijani can't be informed of the situation, but the ambush is a success. The group also successfully find the warhead... but there's a problem. Behrouz has followed them, and special forces are en-route. However, Mossad is also sniffing around too.
What is Peterson's secret? It's a mad scramble for the warhead, and both Peterson and Tamar work together to try and disarm it. He doesn't know where the bypass is, meaning Tamar needs to work quickly and efficiently if they have any hope of saving the city.
At the same time, Faraz is allowed to head outside and call Nahid. She explains she's in a safe place and refuses to let him come and see her. She explains she had a choice and she's taken the option to leave. Faraz has taken his eye off the ball and every step of the way, he's chosen Iran and the regime over her.
When Behrouz appears and looks set to undo everything, he's forced to shoot and kill the guy. Nahid is still on the phone, listening to all of this, so Faraz whispers "I love you" so he knows he's alive and hangs up.
Faraz shows up and holds Peterson at gunpoint, but Peterson bargains with him and demands that Tamar be allowed to go free. He goes for it, and Peterson asks Tamar to speak to Jenn and explain what's really happened throughout the season. He's not a traitor after all - he's a patriot.
When Sepah show up at the tunnel, Ramin guides Tamar out through a series of tunnels that lead to the outside, away from the prying eyes of the special forces.
It emerges that as Faraz ventured outside to speak with his wife, Tamar, she had covertly smuggled the nuclear reactor with her. As for the explosion, it was a relentless force that could not be halted. As the countdown concluded and the explosion ravaged the tunnel, Eric Peterson, Faraz, and a motley crew of soldiers met their demise. The nuclear core was in Tamar's possession, and together, they managed to save the city from destruction. Tamar informed Yulia of her possession, echoing the events of season 2. However, much like before, Tamar was once again forced into exile, as the conflict raged on.
