The episode begins with the Doctor receiving a package from the Kerblam Man. Along with a fez that arrived late (It is assumed that it was ordered by the Eleventh Doctor.), there is a note asking for help. Kerblam is sort of an interstellar Amazon that uses teleporting androids to deliver all sorts of goods, but something sinister is happening inside it.
In the past, technobabble has been used to explain someone teleporting onto the TARDIS (including Huon particles, the TARDIS rebuilding itself, and the TARDIS taking human form), but this was an instance where it did not work. The Doctor tries to avoid what she calls a “teleport pulse,” not knowing it was the Kerblam Man which teleports onto her ship without her lowering the shields. I realize that this is a lot of information for a relatively small plot point in the episode, but we are now expected to accept that a delivery company is advanced enough to overpower Time Lord technology. It is too big a leap for me to suspend my disbelief.
Moving past that, the company runs on a mostly mechanical workforce, and things are tense between the robotic system and the people who work there. A local law requires that at least ten percent of the workplace must be people. It is a bit like an organic affirmative action used to protect those who would easily be dismissed by a biased system. Most corporations would clearly choose a fully mechanized process, as it decreases costs and increases efficiency. As a result, the organics are micromanaged to be as robotic as possible (including ankle monitors to keep track of their movements and limiting fraternization).
In the end, the system was not the villain, or rather, not the antagonist. Fed up with the system, a janitor named Charlie Duffy becomes a radical extremist set on tearing it down. Charlie plans a domestic terrorist attack in order to destroy confidence in automated workplaces. While he is the villain in this episode, the system is not exactly good. It dehumanizes its workers, values profit over people, and even murders an innocent woman just to send a message to Charlie. The company says they plan on increasing the human quotient, but that does not really address the flaws in the system, and the Doctor seems to just let that murder pass without any consequences.
In a move that is intrinsically Doctor Who, Charlie’s plot is simultaneously deadly and silly. The show is known for playing with lethally inane threats to create strange monsters such as an art thief splintered in time, a candy robot, and aliens made of living fat. Explosive bubble wrap can now be added to that list. Charlie lined the protective bubble wrap in Kerblam’s packages with micro explosives that detonate when the receiver pops them. I should probably not be so amused by such a ridiculous concept, but I am.