A businessman, Randy Dancik, is at home preparing a special dinner for he and his wife's anniversary when the lights and television at the house begin to flicker on and off. He walks around the house to check on everything, and a shadowy figure appears behind him!! When his wife arrives home, she finds him sitting in a chair staring blankly at her. She goes to touch him, and he suddenly disintegrates into ash!!
The Fringe team gets called to the scene to investigate. Walter observes that there were no scorch marks on the seat - ruling out a fire or spontaneous combustion. He must have the ashes taken back to the lab to study further. Broyles inquires if he worked at or visited a hospital in the last 24 hours-this is clearly not the first time Broyles has seen this phenomenon.
Broyles, Olivia, and Peter go to Broyles' storage unit where he reveals that he worked on a case four years ago where the victims turned to ash. There were five deaths by the time that the killings ended, and each victim had worked at or visited the same hospital. At the time, he was contacted by an Eastern European man who knew details only the killer would know. He offered to turn himself in if they could decipher his formula. Peter takes a copy of the formula to Walter to study. Olivia receives a phone call informing her that Dancik had visited his mom at Latchmere General Hospital the day before his death.
Our team reviews all employee records looking for a man of Eastern European decent who may have also worked in the DC area hospital that was linked to the deaths four years ago.
Back at the lab, Walter notices that the formula contains a large amount of radioactivity. He uses a Geiger counter to test Dancik's remains for radioactivity to see if the formula has any link to his death. The Geiger counter fails to pick up anything.
At the hospital, a shadow begins to appear through the hallways. Soon after, another victim turns to ash. Olivia receives a phone call -- the team has found a match: Tomas Koslov, a night nurse in the coma unit.
Broyles and Olivia raid the apartment but Koslov is gone. They do, however, discover Russian electronic components and a fingerprint.
Senator Van Horn contacts Broyles and tells him that the CIA is demanding that he cease and desist his involvement in the case. The Russian government also has an ongoing investigation against Koslov for removing property owned by the Russian federation. Broyles, however, refuses to stop. Senator Van Horn sends Broyles information on Tomas Koslov. His real name is Timur Vasiliev and it wasn't property he removed - it was his brother, a Russian Cosmonaut who was quarantined after returning home from a spacewalk. Is the cosmonaut the shadow???
At the lab, Walter has learned that it's not radiation that is killing the cosmonaut; instead, the radiation is what he's after. All five victims were undergoing radiation treatment, and Dancik had recently been on an airplane and likely received radiation from the sun's rays.
Meanwhile, at the Latchmere General Hospital, the lights have begun to flicker again. A nurse sees Tomas about to remove his brother, thus he sedates her and puts her in the bed to take her brother's place.
Walter believes the cosmonaut brought back an organism with him from the spacewalk capable of projecting itself without ever leaving its host, and he says that he'll be able to solve the formula. Broyles leaves a message with Timur that he has the answers he has been looking for.
Meanwhile, Timur has hooked his brother up to a homemade machine that allows him to shock his brother in order to keep the shadow from leaving his brother's body.
Broyles opens up to Olivia about why this case is so important to him. Four years ago, Fringe division had begun to fall out of favor with the government. He began to stop caring about promotions and just wanted to make the world a safer place. In the process, he became obsessed with the cosmonaut case and it was too much for his wife. In the process of trying to protect his family, he lost them.
Timur telephones Broyles asking for the answer to the formula. Walter reveals that the shadow and the cosmonaut have become one. They are bonded at a molecular level that can't be broken-the organism cannot be killed without killing its host. Broyles pleads with Timur to come in and to let them help but he does not respond. He stays on the line long enough for Astrid to track their location.
Broyles bursts into Timur's hotel room and finds half his body disintegrated into ash!!! The team finds the cosmonaut in a van in the parking lot. Walter tries to figure out the machine to keep the shadow from taking another victim. Meanwhile in a nearby hotel room, a young girl watches the television. It suddenly flickers off. She stares into a nearby dark closet. Outside Walter struggles with the machine. Broyles hears the young girl's screams and runs to shoot the cosmonaut in the head just in time to save the young girl.
Broyles visits his wife to let her know that he has closed the case that tore apart their marriage. She is happy for him and invites him in for dinner but he declines. As he leaves their house, a man approaches him. He tells Broyles that he has a friend in Senator Van Horn because when the CIA says to cease and desist, they mean it. He warns Broyles to not file a report. Broyles asks him what they did with the cosmonaut. The man glances up to the stars and tells Broyles that they had no choice once he started breathing again...