The headline on the front page of the local paper in Batesville, Utah reads "Laboratory Accident Kills 4." The man reading the story has an issue with a young woman who enters his convenience store. He blames her for the death of a friend. The man jumps out from behind the counter. He's angry. The young woman feels threatened. Soon items are flying off the shelf pelting the man standing before her. She swears she's not responsible. The man flees the store to find gas pouring onto the ground. BOOM! An explosion rocks the store's exterior. Inside, the young woman is devastated that this is happening to her again.
Ward lets May know that they should continue to keep their secret relationship a secret. Actually, he only tries to let her know this. She's already left him to towel off from his shower alone. The team has a new mission. It involves the woman from the convenience store. Her name is Hannah Hutchins. Coulson lets Skye know that they are headed to Utah to verify that she's a telekinetic. The town of Batesville blames her for the particle accelerator explosion that killed her coworkers.
An angry mob is camped in front of Hannah's house when Coulson and the team arrive. They throw stuff at her on the front porch. Moments later, a police car without a driver speeds toward a protestor. Coulson tackles the man to move him out of harm's way. He tries to calm a distraught Hannah. Nothing is working until... THWAP! May shoots Hannah with a gun that renders her unconscious. Time to go!
Fitz and Simmons send in a dwarf to gather intel on the explosion at the Particle Accelerator Complex. While doing so, they discuss the notion of pulling some pranks on Skye. After all, she is a rookie. They decide to concoct a story as to how May got her nickname of "The Cavalry." It involves killing hundreds of mercenaries and riding in on a horse. Simmons can't help but smile at their little fib.
Hannah is locked in a secure room. She blames herself for the deaths of those four people. She says that she had a technician named Tobias replace a faulty part. As the quality control supervisor, she believes she missed something. Coulson believes the accident may have caused her to obtain telekinetic ability. Hannah believes she's being punished by God. She thinks she's being haunted by demons. As Coulson discusses Hannah's situation with the team, a figure can be seen in the background. It's Tobias. The image is then gone in an instant.
Skye wants a chance to talk to Hannah. She learns the story about May's nickname from Ward, who mysteriously loses the kitchen knife. Skye learns that Tobias filed three safety complaints against Hannah over the course of a month. Fitz doesn't notice the figure behind him as he gathers some supplies. It's Tobias. He grabs a heavy wrench and attacks Simmons in the lab. Once again, he's gone in a flash. Simmons knows Hannah isn't lying. There's someone else on the plane. Tobias cuts the power to the bus. They are going down.
May and Ward make a rough emergency landing in an open field. Tobias knocks out the last remaining radio link. The search is on for the entity that's torturing Hannah. Tobias appears suddenly carrying a large plumber's wrench. He locks Fitz and Simmons in a room. Ward tries to overtake him, but Tobias keeps disappearing in mid-fight. The entity ultimately traps all three agents in a room. He sees the translucence of his hand before letting out a scream of rage. Then he's gone again.
Skye lets Hannah know that something bad is out there. They talk about their belief in God. Skye eventually learns the real story behind "The Cavalry" legend. It wasn't a rescue mission. It was a welcome event that went south. Coulson says May was different before she did what she had to do that day. She used to be a lot like Skye, who is suddenly taken hostage by Tobias. The guy is traveling back and forth between worlds. He wants Hannah.
Tobias goes after May, who pulls a disappearing act similar to his. Moments later, she's dragging Hannah through the woods to a barn. She wants to use her as bait to draw out Tobias. The plan works. Tobias arrives. He battles with May. The entity gains the upper hand quickly.
Back on the bus, Skye realizes that Tobias complained about Hannah on purpose. He wanted her to notice him. He likes her. Tobias intentionally loosened some bolts to see her. When he saw that Hannah was getting blamed, he came back to this world to protect her. May tells him he needs to let her go. Tobias holds Hannah's hand before disappearing forever. May used the same speech Coulson gave to her during that ill-fated event from her past to get this to happen.
Coulson lets Skye know that she's good at reading people. That's why he wanted her to pay attention to this case. It'll help her be a great agent someday. Until then, she'll continue to observe Agent May, who actually lets her take a seat beside her in the cockpit. It won't be easy getting inside May's head though. She's a deep mystery-so much so that no one knows she's the one who pranks Fitz at the end of this particular mission.