“Zero Sum” is episode twenty-one of season four of The X-Files.
At the Transcontinental Express Routing Centre in Desmond, Virginia, one woman asks another to cover for her as she needs a cigarette. They disagree as to the length of time since the last one, and the second woman suggests getting patches as well as gum. However, the first still heads for the toilets and enters a cubicle, waiting for another to leave before she lights up. Bees come out of the sink. Many, many bees. They cover the place. The woman, having fished her cigarette, stands up and notices bees everywhere, and starts flailing. The second woman heads to look for the first and enters the toilets too. There are no bees. The first woman is still there, though, inside a cubicle. Covered in blisters and dead.
Skinner is working on a computer, looking at some files connected to the dead woman, Jane Brody. He deletes them, then leaves the darkened office. Mulder’s office.
Skinner, dressed in dark clothes and wearing gloves, is packing a bag in his apartment. He leaves his phone off the hook and heads to the routing centre. He removes the police label from the toilets and enters, cleaning the place thoroughly, from the cigarette on the floor to the mirror to a smear of what looks like honey on the ceiling. He doesn’t seem happy.
Next, Skinner breaks into the Audrey County Morgue. Hiding from a morgue assistant who hears a noise, Skinner takes Brody’s body and heads to an industrial place where he puts the body into a furnace. The next stop is the police forensics lab in Desmond. He wants to take a look at what they have on Jane Brody. Skinner is told that the techs haven’t been to the crime scene yet, so he asks for what they have. Saying he’s Agent Fox Mulder. Whilst the officer is looking another way, Skinner swaps a blood sample from the evidence for one he brought.
Skinner is dumping this outside when a cop runs after him. Detective Ray Thomas; he’s the one who contacted Mulder, he heard Mulder was there. Does ‘Mulder’ think they have something worth looking into. No, he doesn’t. Skinner says it’s nothing. Thomas was told that Mulder looked into stuff like this, and if it’s nothing, why did he come down in the middle of the night? Just doing his job. As Skinner leaves, someone watches him.
Back home, Skinner changes out of his dark clothing and puts it in a rubbish bag. He puts the phone back on the hook and opens his door to dispose of the rubbish to find Mulder there. Mulder has been trying to reach Skinner; he thinks his phone must have been off the hook. Skinner claims he was getting some sleep. And taking his garbage out at 4 AM?
Skinner asks Mulder what he wants. Mulder was looking into the unexplained death of a postal worker who someone is going to great lengths to keep unexplained. Mulder has photos sent by a detective, but the email files have been hollowed out. Mulder got the photos from Thomas’s partner. After said partner finished telling Mulder how Thomas was shot in the head, execution style, two hours ago. Possibly by the same person who forged Mulder’s name to gain access to the forensics lab. Mulder wants some help. Scully is in the hospital; her oncologist wanted to run some tests. Skinner will take a look in the morning.
After Mulder has gone, Skinner heads to the garage where he meets CSM. Skinner demands to know if CSM killed Thomas or had someone do it for him. He won’t be a party to murder. CSM tells him it only happened because Skinner left the job unfinished. Skinner says they didn’t have to kill Thomas. CSM says Skinner is in no position to question their arrangement, and it’s not that easy to walk away from.
In the morning, Mulder rings Skinner to tell him the body is gone. He also has discovered the blood has been swapped. The gun that killed Thomas was a Sig Saur P228. Skinner checks his desk; the gun he kept in there is gone. It looks like Thomas was killed with Skinner’s gun. Skinner rings CSM and demands to know if that’s the case. CSM mocks him and, when Skinner says he will go to the police, asks him why he’s calling CSM instead of doing that. The less Skinner knows the better. The reason why Skinner is doing this is revealed; he made a bargain with CSM for a cure for Scully. Scully then heads back to the bathroom at the routing centre and. after seeing another smear, breaks open the wall. Inside is a massive honeycomb.
This episode is all about Skinner. Mulder has very little screen time in it, mostly sounding suspicious of Skinner even before he finds out that Skinner is involved, and Scully doesn’t appear at all.