In the briefing room of the bus, Coulson tells the agents about their mission to track technology on a train in Italy, believing it will lead them to Ian Quinn. Going undercover, the agents pair up (May and Ward, Skye and Fitz, and Coulson and Simmons). Ward and May abandon their disguises and suit up in a first class compartment. May climbs to the top of the train just after telling him that she let Coulson know about their relationship.
While pretending to ask for recommendations from a train conductor, Skye snatches the keys from his uniform and she and Fitz slip into the luggage car.
Because Simmons is horrible under pressure, she tells Coulson that she has a backstory for her undercover persona. As their target walks by, Jemma causes a scene to distract him and Agent May, using x-ray goggles, scans the train from the roof to find the technology they are looking for. Soon the agents' communication systems go staticky. To investigate the problem, Coulson leaves Simmons, walks the length of the train, and, when Ward rushes in, the two jump from the back of the train. Grant's pursuers toss a grenade from the train which causes the train to seemingly disappear.
Skipping back a few moments, Agent Ward leaves the first class compartment, dressed as a conductor. A rich traveller asks him to carry a heavy bag into her personal compartment, but she reveals that she and a hidden man inside are working against S.H.I.E.L.D. for Quinn. Grant tells Simmons to lock herself into the luggage car along with Fitz and Skye. As she leaves, three suited men chase him and he and Coulson must leap from the train. Coulson says Fitz-Simmons and Skye will be all right if May is there but Ward discovers her goggles on the ground. They run through a vineyard to get away and "borrow" a hotwired truck.
When they return to the bus, Coulson picks up a video call from Signore Russo, their contact in Italy, who says Cybertek knew they were coming. He begins coming to the Bus to meet up with them, while Ward tries to examine the grenade found at the scene. Coulson and Grant are both confused by Fitz-Simmons's holotable. Ward says that he did not want Coulson to know about his relationship with May. Coulson tells him that if anything goes wrong because of the relationship, Ward will be reassigned to Alaska to guard Emil Blonski. When Russo shows up at the bus, he enters but a knife, thrown by May, penetrates his back and he falls down dead.
Returning to a scene on the train, May finds the tech but the men guarding it shoot her and she parachutes from the train. Nearby she sees Coulson and Ward both under the effect of a dendrotoxin and runs off to hotwire the truck which is later found by them. As soon as she starts it, she is taken at gunpoint by Russo and his men.
May awakens in the Italian countryside, hanging from the roof. Russo stabs her shoulder with a knife, just the weapon she needs to take down Russo's men and wound Russo's face. He drives away in a hurry but she follows him. When Russo drives up to the bus, he has a gun poised to take down Ward and Coulson, but May throws the knife and it lodges into Signore Russo's back.
While the plane flies to the train's location, Coulson helps her stitch up her stab wound. May expresses her faith in the three agents left on the train.
In the stopped train, Fitz and Skye cannot be found, but laptops with bullet holes and Simmons firing the night night pistol are discovered in the luggage car.
Taking a look back a little, Fitz and Simmons talk about 0-8-4's in the luggage car. She asks if an 0-8-4 could be a person and he says he'd be scared to meet him. When communications go down, armed men burst in and are taken down by Skye. One man, wielding a grenade, almost unleashes it on the agents but Simmons rushes in and traps the blast between herself and the bad guy. Fitz identifies the effects of a dendrotoxin. The train stops and when a package is unloaded from the train, the two track it to Quinn's location.
Stealthily, Fitz triggers an electronic beacon to contact the agents and Skye goes in firing a night night pistol. Fitz begins disabling the cars in the driveway. The Cybertek associates prepare the tech for Quinn but Skye sneaks downstairs and discovers Michael Peterson in a hyperbaric chamber. Ian Quinn and a guard sneak up on her and disarm her. Quinn removes Mike from the chamber and puts the top-secret technology, a fully-electronic prosthetic cyborg leg on Mike to replace his missing limb. To test Mike's loyalty to the clairvoyant, Quinn asks the cyborg if he would kill Skye. When his answer is that his orders are to kill someone else, he leaves but Quinn shoots Skye twice and leaves her for dead.
Because the Cybertek employees led S.H.I.E.L.D. to Quinn's hideout, Mike is ordered to take out every one of them. When the agents rush in, Mike is ordered to leave without engaging. May takes Quinn prisoner. Coulson finds Skye's lifeless body and they are able to restore her pulse and respiration using the hyperbaric chamber, but her temperature remains deathly low.
Back on the bus, the agents must rush Skye to a medical facility. Fitz comforts Simmons because of the shock of the situation. Angrily, Grant leaves the room. May tells him that this is not his fault.
In a park, Mike watches children play. He writes "Can I please see my son?" so that his handler can see it. The person on the other end answers "Not yet" and after a much closer look at the Cybertek prosthetic leg, it is revealed to be "Project: Deathlok".
- Stan Lee makes a cameo in this episode, in similar fashion to his cameo's in Marvel Movies.
- Emil Blonsky was referenced in this episode, and confirmed to still be under S.H.I.E.L.D containment after the events of The Incredible Hulk.