When Brother Adrian goes head-to-head with Artie in the Warehouse, only to slip into the shadows before Myka and Pete arrive, Artie sees that he has to come clean and bring everyone in on the hunt. As they're strategizing, they learn that Adrian has sent out more artifacts, this time to those dearest to the agents - Myka's pregnant sister, Pete's ex-wife, and Claudia's brother, Joshua. All three agents rush to their loved ones while Artie and Leena stay behind and strategize on how to stop Adrian. Mrs. Frederic and Jinks head to the Vatican to see if they can alert the brothers of the Knights Templar to Adrian's actions.
When Pete arrives in Yuma, Arizona, Amanda is burning with fever and reports receiving a present by mail from her husband, who's traveling abroad. Pete bags the gift, a leather box, but nothing happens. Later, when Amanda is hospitalized, Pete sees a tattoo of a cat through her hospital gown, and as soon as he touches it, it transfers itself to his body. Artie, in a clipped Farnsworth conversation, tells Pete to cut, burn, or goo it off, but the tattoo moves every time Amanda goes near it. As the army base's radiation alarm sounds, Pete realizes he's wearing a nuclear bomb and they rush Pete to a bomb shelter to protect the population from a nuclear blast.
Myka is dealing with some heavy sibling rivalry - Tracy's eyes glow green and she tries to kill Myka, who finally restrains Tracy and goes through piles of baby gifts, looking for the artifact. She's running out of steam when she gets a goodbye call from Pete, but when she hears that Amanda received a leather box, she tells Pete to press the tattoo against it. Her theory - that it needs skin-to-skin contact to transfer - is solid. Pete bags the box just in time, and Amanda cries tears of joy that he's not dead.
Pete then hurries to Colorado where he and Myka dig through the trash, finally finding an old-timey looking cord. It barely reacts to the bag, but when they cut it, and a flash of light erupts. Tracy is back to normal, but has no idea why she's tied up or how her nursery got to be such a mess. Just then, Pete gets a call from Claudia. He tells her that even though everyone's fine - including Claudia's brother, Joshua - he's getting a really weird vibe. Claudia tells him that she thinks it might be Artie, who, though he expressed surprise that Joshua was in Menlo Park, was actually the one who assigned him the job.
Mrs. Frederic and Jinks, in a secret chamber in the Vatican, have discovered a painting framed with wood from the Tree of Life, and in it are trapped some half-dozen brothers of Adrian's order. Mrs. Frederic releases them and hastily explains what they're doing, but when Brother Adrian steps out of the painting with no knowledge of Artie's plight - a confirmed truth, thanks to Jinks's lie-detecting ability - they realize the threat is in their own home.
Mrs. Frederic realizes that Magellan's astrolabe must have caused a psychotic break in Artie, and he is the one who has been wreaking havoc with artifacts. She urges Leena, who is trying to help Artie out of his violent delusions, to leave the Warehouse immediately, but it may be too late as Artie's psychosis takes hold and he issues a deadly blow to his trusted friend.