When last we saw our heroes, they’d arrived on the Moon, where a plague was happening.
There’s a Cyberman menacing Jamie. It takes away one of the other patients and leaves, with Polly spotting its departure. She knows it’s a Cyberman, but neither she, Ben, or the Doctor can convince the base commander.
The Doctor is given 24 hours to figure out what’s killing the people at the base. Polly asks if he’s a medical doctor, and he seems to vaguely recall getting a medical degree in Scotland in the 1800s. Well, at least that’s better than getting a tooth extracted by Doc Holliday.
In the command center, people continue to try to figure out why their weather control technology isn’t working as it should. Some of them do this while wearing shower caps, for some reason. Anyhow, the weather is going haywire, and we really spend quite a bit too much time focusing on the minutia of weather control operations.
The Doctor is wandering around trying to get samples of various things. This is not well-received by everyone, including a French man who curses him out in French. As to why the TARDIS doesn’t translate it, that’s anyone’s guess.
As that’s happening, the Cyberman shows up in sick bay again. It uses Force Lightning to knock out Jamie and Polly and wander off with another person. The Doctor arrives just after the nick of time.
The pacing really suffers with this story. There’s entirely too much time spent with the guys in the weather control center. We do need to check in with them periodically and see what they’re up to, but we get minutes at a time watching them. It gets a bit dull.
The Doctor fails to find a cause of the illness. Polly, who is settling into a deadpan snarker role, asks if it’s just possible that there might be things that Lister didn’t know in 1888 that might be relevant to their current situation.
Polly makes some coffee, and everyone is starting to settle in when one of the men who drinks the coffee collapses, clearly showing signs of the same illness as everyone else. Dramatic.
The Doctor finally figures out that what’s causing the disease is…the sugar! Not everyone has sugar with their coffee, but those who do succumb immediately. Not a bad twist, as it turns out. The Doctor then experiences one of those, “the killer is in the room with us!” kind of moments, and we have our cliffhanger!