Twenty miles outside of Philadelphia at the West Chester rebel camp in an abandoned factory, Miles is chained to a chair. His eyes are weary and blood gathers around the corners of his lips; he's been taking quite the beating. Rebel leaders Colonel Starkey and Sargent Wheatley question Miles: why shouldn't they execute him and the rest of the gang immediately? After all, he used to be the Commanding General of the Monroe Militia. Miles offers a deal: if the men help him save his captive nephew, Miles will deliver Monroe's head on a platter. The rebels don't trust Miles, so he reminds them he knows the ins and outs of Monroe's office, where he dines, even the women he sleeps with. It's an offer they shouldn't be able to refuse - a clear shot. Despite their skepticism, the rebels agree. They'll all be heading to Philly the following night.
By the time night falls on the camp, Miles is walking around with a bottle, drinking heavily. When Charlie suggests he take it easy, he merely laughs. Doesn't she realize they'll probably all be dead tomorrow? What if Miles has to go face-to-face with Monroe? Charlie presses for details, but Miles walks away, lost in thought. The following night, Wheatley and a young rebel named Ashley are eyeing two militia soldiers guarding a subway tunnel. Ashley confidently cocks her longbow and hits both men directly in the chest. She's a pro. The rest of the crew gathers around Miles, who explains that because the walls around Philly are 30 feet high, they must infiltrate Monroe's compound using the tunnels. After lighting their torches, the group vanishes into pitch darkness.
Miles and company are slowly making their way through the torch-lit void. Miles thanks Wheatley for talking Starkey into doing this, but Wheatley makes it very clear that if they don't kill Monroe, he'll put a bullet through Miles' head. Either way, it's a win-win. Meanwhile, Charlie asks Nora what Miles was like back when he was in charge of the Militia. Nora explains that Miles and Monroe were best friends. They grew up together, even enlisted together. Miles left the Militia because he attempted to assassinate Monroe, but couldn't go through with it. All of a sudden, a ratcheting noise echoes through the tunnel and Nora, panic in her voice, orders everyone to stop. Investigating, Nora discovers a landmine directly beneath Charlie's foot.
Back in Philly, Rachel's hard at work over a complicated looking machine, drill in hand, as "Since I've Been Loving You" by Led Zeppelin slinks out of the speakers of a CD player mournfully, the pendant close by. Neville strolls in to introduce Captain Burke, insisting Rachel explain what she's building. Rachel explains the pendant acts like a wireless battery, powering anything in its range. The issue? That range is limited to about 10 feet. Rachel's machine will amplify the pendant's range to about half a mile, powering things like tanks, jets and missiles. Neville can barely mask his excitement. "When will it be ready?" he asks. Rachel glares at him. "You mean when will he be able to use this machine to murder thousands? Soon."
In the subway tunnel, Miles and Aaron are sick with worry. Nora marks mines with spray paint, then orders the group to keep moving before they blow themselves up. Wheatley and the rebels move down the tunnel slowly, but Miles and Aaron decide to stay. Terrified, Nora gingerly unscrews a small plate on the mine. Charlie breathes heavily, perhaps the last breaths she'll ever take, as Nora slowly pulls the fire pin out. She thinks she's got it, but for all she knows there may be a second trap below it. Nora outlines the course of action: Charlie will step off the mine and unless they immediately get blown to pieces, they'll all run like hell to the end of the tunnel. NOW! The four of them take off running as mines begin to explode behind them one by one, flames licking the heels of our heroes. Charlie and Miles collapse, ducking beneath the shrapnel. It's a close call, but they're safe. Looking behind them, they see the front of the tunnel is completely boarded up with debris.
Seeing as close calls with death are becoming the norm, the group has no choice but to continue on their way. Aaron strikes up conversation with Ashley, asking why she's fighting so hard for a country she's too young to remember. We learn Ashley's dad left Syria because he didn't want his children to grow up scared in their own country: he believed in America, loved it even. She's doing this for him. When she asks Aaron why he's fighting Monroe, Aaron's taken aback. He is fighting Monroe, yes, but up until this point, he never quite looked at it that way. Suddenly, Miles spots a Militia scout in the shadows and charges after him, Charlie and Nora at his heels. Seeing the scout enter a closet, Miles yanks open the door, but no one is there. Charlie and Nora think Miles may be going a little cuckoo, but he swears he saw someone. He's perplexed: the guy couldn't have just vanished into thin air...?
Descending further into the tunnels, the group walks waist deep in sewage. Falling behind, Nora stands still for a moment, uneasy. She senses movement to her left, then her right. Eyes wide, she stares closely into the water when BAM! she's forcefully yanked below the surface. She thrashes around wildly, screaming for help as Miles, Charlie and Aaron wade towards her. Nora tells them an alligator bit her leg, but Miles assures her that her leg is fine. There are no alligators! Nora's baffled. It all felt so real... That's when it hits Aaron. When the tunnel collapsed, their air supply was sealed off. They're all beginning to hallucinate because they're slowly suffocating. Panic races across their faces. If they don't escape the tunnel soon, the lack of oxygen will kill them before the Militia does.
Progressing with a new sense of urgency, the group finds themselves at an exit, only to find it's been sealed off. Devastated, Miles claims there's no other exit, but Charlie and Wheatley insist they've got to find another. As the group begins to follow Wheatley, Miles lags behind, barely keeping his eyes open. He spots a crack of light coming from an open door. He opens it slowly and walks into Monroe's office, as the volume turns up on "Kashmir." Smiling, Monroe welcomes Miles with a big hug, then pours cognac into two glasses and hands one to Miles, assuring him that yes, this is a hallucination. Monroe asks Miles if it was worth leaving the Militia and trying to assassinate him. Why did he do it?
Miles retorts quickly: Monroe went too far. But Monroe believes Miles regrets abandoning the Militia. If Monroe takes him back, Miles just might sell out his friends and fall right back into line... The pained look in Miles' eyes confirms Monroe's suspicions, but just then Charlie rousts him out of his hallucination. As they catch up to the group, Charlie commands Miles to keep it together. They'll die without his leadership. In the flickering of the flames, Aaron sees his wife, Priscilla, walking beside him. He forces himself to stare straight ahead, but Priscilla won't let him. Why did he leave her? He's been so strong for Charlie... why couldn't he be that strong for her? Maybe he never truly loved her. We see Aaron's heart shattering into pieces as he continues to ignore Priscilla. He pushes on, leaving her behind in the dark.
After what seems like forever, Wheatley notices his torch is burning brighter again, which means fresh air should be close by! The group stumbles upon a service door and Wheatley and Miles work together to tear it down. As light fills the hall, joy filters across the faces of the group, but not for long. Out of left field, Wheatley produces a gun and shoots down two of the rebels as Charlie, Nora, Aaron and Ashley duck for cover. Wheatley shuts the door and bolts it from the outside, putting his gun to Miles' head. Wheatley is a Militia man, and Monroe is going to want Miles alive. As the others down below attempt to break down the door, Wheatley leads a stunned, quiet Miles up the tunnel.
Wheatley's surprised Miles didn't remember him: after all, he pinned a medal on him during the Trenton campaign. Turns out Wheatley's been working undercover the whole time. He knew the Girard exit was sealed off. Just then, Aaron succeeds in breaking down the door, and the foursome quietly spills out into the hallway, weapons (stolen from the dead rebels) at the ready. Ashley eyes Wheatley, ready to shoot her infamous bull's eye, but Wheatley's quick and shoots her dead, square in the chest. Charlie reacts quickly and aims her crossbow, successfully shooting Wheatley in the chest. As he staggers back, he takes one final, wild shot, which hits Charlie. She falls onto the steps, cracking her head against the concrete.
Charlie's eyes flutter open as she tries to gather her bearings. She sits up, finding herself in the Matheson's Wisconsin home, where Ben is washing dishes. Charlie winces as a searing pain settles across her head. Her father's supposed to be dead... but there he is, casually telling her to go get Maggie and Danny for dinner. Ben assures her it was all a dream, and she's safe now. She doesn't ever have to leave, and neither will he. As rays of sunlight dapple through a large window and Ben helps Charlie lie back to rest her head, the scene cuts to Miles, frantically asking Charlie to open her eyes. His face is twisted in pure agony. After all they've been through, Miles can't bear to lose his niece. He doesn't understand! The bullet just barely grazed her! Nora reminds him Charlie cracked her head pretty hard, not to mention the hours of oxygen loss.
Desperate, Miles assures the silent Charlie that he'll get Danny back - she just needs to open her eyes! Hearing Miles' voice from a distance, Charlie realizes she's dreaming. As much as she wants to rest, like Ben suggests, she's got to get Danny. She hugs her father, telling him how much she loves him. Back in the present, Charlie finally opens her eyes as Miles, Nora and Aaron all breathe a sigh of relief. Even Miles looks like he's ready to cry. Hours later, Charlie is sitting up, holding a rag to her head wound. Miles wants to spend the night in the tunnel so Charlie can regain her strength, but she wants to press on. With a smile, Charlie tells Miles it was his voice that helped her escape a place that was so hard to leave. Miles nods. It's crystal clear he's starting to need Charlie just as much as she needs him.
It's nighttime, and the group finally decides to leave the tunnel. They have no idea what awaits them outside, probably a Militia ambush, but they walk through anyway. Meanwhile, Rachel's busy working on the amplifier. Monroe walks in, an edge to his voice. He reveals that Neville has a hunch Rachel isn't building what she says she is, so they've decided to solicit a second opinion. Neville brings in Dr. Jaffe, looking beaten down. After inspecting the machine, Jaffe insists it's a sophisticated time bomb, which uses the pendant as an electric trigger. This enrages Monroe. "You're dead," he spits, "and Danny's dead." Monroe doesn't need Rachel anymore, especially now that he has Jaffe, who's been a hell of a lot more cooperative.
As Monroe heads out of the room, Rachel turns and stabs Jaffe right in the heart with a spare screwdriver. He falls to his death, moaning as blood drips across his shirt, as she sobs in apology. Then she turns to Monroe. "Now you need me," she says as guards drag her out of the room. Monroe looks after her, eyes blazing at this unexpected turn of events.