Pete, Myka, and Artie address the Regents and Pete speaks in defense of his friend, insisting that he did what he did to save the world. None of what happened was really Artie, and Pete insists that Warehouse 13 doesn't work without him. Adwin Kosan tells him that they've already reached that conclusion and that there is no reason to punish Artie. They give Artie Leena's video statement and reinstate Artie, but Artie insists that he killed her. Adwin asks if Artie was the one who killed her, but Artie isn't comforted by the fact that he was under the influence of the astrolabe. Claudia and Steven watch from the gallery and Claudia realizes that no one said anything about how she had to stab Artie to save him.
Back at the warehouse, Artie refuses to discuss things further and goes up to his room. Myka insists that they should pursue the matter but Pete isn't convinced. When Myka wonders where Claudia is, Pete says that she went to the B&B and might be avoiding Artie. He figures that some new case will come up.
A man runs through the Cowan National Forest in Oregon, yelling for help over his phone. He drops it, trips, and falls into a ravine, and someone directs a beam of light at him. The man sinks into the earth while his killer uses the same light on the discarded cell phone... and then carves a symbol into a nearby tree.
Pete and Claudia are soon called in when someone reports a tremor. They find the body and have the local authorities remove it, while Claudia stumbles through the brush. Myka figures that it will do her good to get her out of the warehouse. The local ranger, Evan Smith, pulls up and Pete introduces himself. Meanwhile, Claudia slaps at mosquitos and notices the carving on the tree. As she walks over to it, she steps on the cell phone and digs it up. Pete comes over as Claudia confirms that it's been all but destroyed. They check the dead man's wallet and discover that he's Linus Bentley, the head of Qualcast Communications. There's no artifact on the corpse and the agents figure that the killer used it to kill Bentley. Claudia hooks up to the Internet and discovers that the communications company has drawn the anger of local environmentalists who claims that the signals are disrupting local wildlife.
Myka and Steven go to find Artie, who is wandering through the warehouse. They find him cutting open an artifact with a sword and scream. Artie explains that he's redistributing the energy and is angry when he learns that Myka sent Pete. He quickly regains his temper and tells Myka that whatever she does is fine. They notice that Artie is working from a list and look at it, and discover it's a list of things that Leena did to keep certain artifacts in balance. He takes the list and says that he doesn't need their help, and goes off on his Segway.
In nearby Bicknell, Claudia and Pete visit the environmental group, Green First. They talk to the leader, Autumn Radnor, who assumes that they're volunteers. Pete identifies himself and asks about Bentley, and Autumn assumes that Bentley is using the government to intimidate them. When they explain that Bentley is dead, Autumn is seemingly shocked and says that she has to go. Claudia and Pete discuss the case and wonder about Autumn's about-face. Claudia clones Bentley's phone and discovers that he made a call to a local cannabis shop dedicated to organic healing. They go there and call for the owner, Geoff Nevins. They get no answer and find the answering machine. Bentley left a message for Nevins saying that they know. The agents spot a blue glow in the back and find an indoor cannabis farm. The same carving is drawn on a white tarp and beneath it is Nevin's corpse, his mouth filled with dirt.
As Claudia checks the warehouse files for earth-moving artifacts, Pete recognizes the symbol from somewhere else. They go online and Pete finds a reference to the Last People on Earth, an eco-terrorist group who used the same symbol. They vandalized logging sites in Oregon, operating out of Cowan National Forest for two years. Their leader, Ryan Clayton, was captured and died in prison two years ago,. The agents figure that someone in the group is using an artifact, and the FBI located a cabin in the woods that they used.
At the warehouse, Myka and Steven find Artie in the Zen garden where Leena worked. Leena used the spiral inside to interpret an artifact's energy and properly place it. Artie is using the room to analyze a porthole artifact from the Norge
and sits down. The room glows with energy and finally an indicator on the spiral shows the symbol for "great sorrow." Artie assures them that he's not going to beat himself to death and walks off.
Evan leaves the agents at Ryan's cabin, which was ruined in a fire. Pete finds a Henry David Thoreau quote carved into a beam and they remember that Autumn used a similar quote. The agents drive to her house and go in, guns drawn. They find her bags on the bed and check the closet. Autumn sprays Pete in the face with pepper spray. They quickly subdue her and she explains that she was a LPE member along with Linus and Geoff. Autumn figures that someone knows who they were and is killing them one by one.
Autumn shows them a photo of her and her friends. Also in the photo are Annie, who died of cancer two years ago, and Ryan Clayton. The group met in college and set out to protect the forest from Lockhart Logging. Autumn admits that they were idealistic and stupid, and things got crazy as they went after bigger targets. Someone finally got hurt so they walked away. Pete figures that Haddon Lockhart, the head of the logging company, has a grudge against them. He was the one who was hurt in the explosion and Pete goes to talk to him while Claudia watches over Autumn.
In the warehouse, the porthole glows briefly. Across the aisle, an artifact sprouts vines and the vines knock over a soccer ball. It falls off the shelf and sets off a RC car, which bumps into a crate, and something bursts out.
Myka asks Artie if he's going to watch Leena's video statement. He says that it won't change anything, but Myka says that when she made hers, it made her realize how important their jobs were. Artie insists that Leena didn't understand what she was agreeing, but Myka tells him that they all did and tells him to watch it. They receive an alert from the section where they put the porthole and realize that it's bad.
Pete meets with Haddon and reveals the burn tissue on his shoulder. He complains about the millions of lost revenue and hundreds of lots jobs, and explains that the FBI received an anonymous tip that led them to Ryan. Haddon shows him a clipping of the day that he testified against Ryan in court, and says that the eco-terrorist was a monster. Pete examines the clipping and spots a familiar face in the background.
Autumn shows Claudia photos of her and her friends. Claudia asks if she had any regrets about her activities and Autumn says that she made some bad decisions. However, she insists that they did good things and she came to believe that what she was doing mattered. Claudia says that she got into a fight a couple of weeks ago with her boss and had to do something that she thought could help him... or kill him. She assures Autumn that she didn't kill her boss, but now she doesn't know what to do about it. Autumn sympathizes but warns her that things don't become any clearer when you get older.
Autumn and Claudia hear in the kitchen and go to investigate. It's Evan, and Autumn explains tells Claudia that he's Ryan's brother. He has a lantern with him and uses the artifact to blast the floor open. The impact knocks Claudia out and Evan drags Autumn out. He says that one of them betrayed his brother and now he's going to get justice. Pete arrives and orders Evan to drop the lantern. Evan uses the artifact on Pete, burying him alive, and drives off with Autumn.
Claudia runs out and sees Pete going under, and pulls him up just in time. Pete explains that he saw the photo and figured out that Evan was Ryan's brother. They head out to find Evan and figure out why he kept Autumn alive.
In the warehouse, Myka and Artie find Steven, who has taken cover. Artie takes out one of Claudia's "goo-nades" and tosses it, spraying neutralizing fluid everywhere. They trace the path of destruction and Myka finds a crate labeled "Da Vinci's Gargoyle." The gargoyle swoops down at them.
Pete and Claudia break into the ranger station and confirm he isn't there. They search the place and find Ryan's old journal, and realizes that the group used code names. Evan deciphered them and went after his brother's friends, and they figure that Evan's next target is Haddon. They drive to the logging camp and discover that Evan has used the lantern to create a chasm. They borrow some ATVs and go cross-country.
The trio ducks the gargoyle and take cover, and Artie explains that it's a clockwork creature that was built to guard the Vatican. Steven checks the records and discovers that it shut down when it was hit by lightning. Artie realizes that a Tesla won't generate enough energy but spots a coil of piano wire.
Pete and Claudia get to the logging camp and try to warn Haddon, but he refuses to believe that he's in danger. As Claudia comes over, Pete spots a nearby cliff and gets a vibe, and realizes that a landslide could bury the camp. The cliff starts to come down as Evan uses the lamp. When Autumn warns him that he's killing hundreds, Evans says that Ryan never gave any of them up. He read the journal and knows that Ryan loved her, and Evan saved her last so she could see everyone die and then be left to take the blame. Pete and Claudia arrive and stun Evan with their Teslas, but he drops the lantern and it falls off the cliff and lands on a root.
Artie and Myka rig up the piano wire to a generator and a crossbow bolt while Steven goes out to act as bait. The gargoyle flies down on him and Steven runs down the aisle past his friends. Myka fires and hits the gargoyle, and Artie throws the switch on the generator. The gargoyle crashes to the ground and they try to work out what happened. Artie says that the spiral was clear about what emotion was involved, but they wonder if there's something wrong with the spiral.
Pete prepares to have Claudia hold onto his belt and lower him down. She points out that she's lighter and he reluctantly agrees. They hold onto the belt and Claudia grabs down and grabs the lantern. Pete and Autumn pull her up and they bag the lantern.
Artie goes back to the spiral and discovers that each time he tries, they get a different symbol. The emotions have no connection to the porthole and Artie prepares to put it away in the ovoid, but Myka suggests that Artie might be the problem. The spiral read Artie instead of the artifact, and he wonders how he can do it. Myka tells him that he can do it with them. He gives Steven the porthole, smiling, and the agent gets the proper symbol.
As the police take Evan away, Autumn tells Claudia that she was the one who called the FBI on Ryan. Ryan had turned violent and wanted to kill people rather than places. She couldn't live with it and called the FBI. Claudia says that she didn't have a choice, but Autumn says that she stayed away because she was scared and because Ryan asked her to. The woman says that Ryan needed all of them and walks away.
Later, Artie finds Claudia in the office and congratulates her. She hugs him and says that she did what she had to do, and Artie assures her that he knows. When Claudia says that's it, Artie says that there's one last thing and thanks her. Once she leaves, Artie picks up Leena's video and plays it. On it she says that she understands and accepts her responsibilities, and wants to make the world a safer place. Artie breaks into tears and says that he's sorry.