Warehouse 13 Episode 4.10 We All Fall Down

When Claudiareturns to the Warehouse, she refuses to believe that Artie could've murdered Leena, but when Artie, in hologram form, projects himself in front of them and demands the astrolabe, she sees it's true. Pete, Myka, and Mrs. Frederic - also struggling with the hard truth - tell Claudia about the astrolabe's power to cause a psychological break and form an evil in the user strong enough to cause the death of thousands.

Artie set a fire in the Warehouse's Holy Roman Empire sector, then fled, and while investigating the wreckage, they learn what he's looking for: A blue orchid that has the capacity to release an unstoppable plague. Pete is distracted from the ashes by a vision of Leena's ghost. He tries to shake it off, but he can't fight her pull, and follows the specter through the Warehouse to an ominous room. She gestures to a cabinet that houses all of H.G. Wells's research on the dagger that Artie so feared, a dagger that Mrs. Frederic tells them that can pierce any object. She believes Artie means to use the dagger to release the orchid from its impenetrable case, causing a reality so awful that they'll have no choice but to use the astrolabe again.

Pete and Myka rush to Prague to get the dagger where they encounter Artie. He's armed with artifacts, and the vicious half of his personality condemns them before binding them in a noose artifact. Jinks and Claudia seek the orchid, but Artie is ahead of them, as well. The orchid, too dangerous even to be in a Warehouse, has been safeguarded by a local family for generations. He's convinced the keepers of the orchid that all other agents seek the orchid for its destructive purposes, so the Warehouse team intercept Artie at a remote mill, they have to fight through the orchid guards first.

Myka manages to retrieve the dagger and throw it into the mill to be crushed, but Artie uses the barometer from the USS Eldridge to stop time and retrieve it. As he lifts the dagger to release the orchid, Claudia implores the good part of Artie, the part that they all know and love, to fight the evil part. His eyes show his struggle, but the darkness triumphs. He tells Claudia he bears no love for any of them, and with the words, "I cast you out," he drives the dagger into the orchid case.

The impact sends the dagger flying. In an epiphany, Claudia understands a deeper meaning of the words Artie just uttered. Repeating them, she dives for the dagger and plunges it into Artie's heart. The orchid, meanwhile, has dropped to the ground, and as it dissolves into ashes, it is carried by the wind into the mouths of the agents, and is off through the countryside on a pestilential wind.