In this found footage-style episode, the Doctor and Clara arrive on a space station overrun by sand monsters.

The rescue team: Nagata, Chopra, Deep-Ando, and Grunt 474
Plot Summary
Contact with Le Verrier space station in orbit of Neptune has been lost; a rescue team arrives to see what’s up. They run into the Doctor and Clara, who have also arrived, as well as a couple sand monsters.

The Doctor and Clara examine a Morpheus pod
We learn that in this future, Morpheus pods allow people to get a month’s worth of sleep in 5 minutes to increase work productivity. However, a side effect of these pods is that whenever they’re used, they create sand monsters made out of sleep dust.

Sandman
Surviving the Sandmen
So, one by one the rescue party falls prey to the Sandmen. The Doctor and Clara find the inventor of the Morpheus pods on the station, but he is in league with the Sandmen and wants to get them off the station so they can propagate on Earth, rule the cosmos, etc.
Anyway, he dies, his plans are foiled, and the Doctor/Clara/rescue team survivor get away.

Dr. Rasmussen, inventor of the Morpheus pod
Thoughts
This episode’s found footage gimmick actually wasn’t as bad or distracting as I thought it would be. I feel it was added because the story was paint-by-numbers and instantly forgettable, like the episode 42.

Nagata, Clara, and the Doctor
The writer tried to be clever by going meta towards the end, having the Doctor review video footage and wondering who shot it since there were no cameras and that, hey, it’s the sand in everyone’s eyes – the sand was watching them the whole time! But this really wasn’t needed.

Nice view
Another scene that wasn’t needed? The station’s computer forcing Deep-Ando (a member of the rescue team) to sing the Mr. Sandman song to open a door while on the run from Sandmen. Came across as too puerile.

Dr. Rasmussen melts into mucus dust
The sand monsters being made out of human rheum was incredibly preposterous and a cheap attempt to make “nightmare fuel” for the child audience who hides behind the sofa during the show’s frightening parts. Seriously, monsters made out of mucus? That’s a new low.
If memory serves (a phrase favored by Mr Spock), I watched this episode and found it and its found-footage style very confusing. Perhaps I was not in the best shape at the time of watching. Thank you for the summary; I now understood what the episode was about!