On his quest to prove that he's not a good man, Doctor departs to meet Robin Hood. If he could show that Robin Hood isn't real, that would mean good men are not real. Unfortunately Robin Hood is real.
Meanwhile, robots terrorize the countryside with their cross-shaped lasers. This probably symbolize oppression of native Celtic population by Christian Normans or some shit (Gatiss is well known to hate immigration). They collect gold to make world's largest microcircuit.
The Doctor, Robin Hood and Sheriff of Nottingham all compete in archery contest in which the latter captures the first two and make them banter in the cell. Doctor tried to demand enlightenment, but no Eternals take his bait.
There's some escaping, showing of Ramon Salazar's early acting career before he became a supervillain, and a riot in which robots kill themselves with lasers bouncing off mirrors (lol, dumb robots). As Sheriff flies away, Clara, Doctor and Robin shoot the ship with golden arrow causing energy surge, proving that Mark Gatiss is more than qualified to become the next showrunner - while Moffat forgets what was going on in the plot over the season, Mark managed this feat over the single episode.
Fairly comfy. Even though doesn't really deliver what it promises. There isn't a singular robot and one that stands out is more of cyborg and it's only apparent in deleted scene. Also, they are in Nottingham, not in Sherwood, which is probably nearby, but like saying that London is in Atlantic Ocean.