“Thin Ice” is episode three of season ten of the new Doctor Who.
At the end of the previous episode, “Smile”, instead of the Doctor successfully taking Bill back to the university in time for the kettle to finish boiling, as he had promised, the TARDIS had materialised somewhere else. Not exactly a huge surprise; navigation has tended to be a bit erratic over the years. This does mean that Nardole is with them.
This episode opens with the TARDIS in London, where it’s snowing. Bill thinks they’ve gone to a parallel world; they’ve actually gone back to February 4th, 1814, the last of the great Frost Fairs, held when the Thames froze over. The Doctor moves the TARDIS, as it is parked on the frozen Thames the day before it thawed out. Bill points out that 1814 may not really the best time for her – slavery does still exist. As Bill goes back into the TARDIS to get a dress, a man bumps into the Doctor and drops his basket off the bridge onto the Thames. A boot is dislodged from the ice, sings below the water, and lands on something. Something scaly with a very big eye, scales, and very big teeth. Which appears to have just woken up.
Bill is worried about what will happen if she accidentally changes the past. She says that anything she does could change the future. The Doctor points out that this is just like every day of her life. True enough. So Bill eventually decides to have all the fun of the fair. Whilst enjoying herself – and noticing that there are rather more non-whites than she had been brought up to believe in Regency England (not that surprising really; London is the capital of a world-spanning empire with ships and visitors from all over the planet) – she sees a green light under the ice. Then two. Bill is worried that they may be physical symptoms of time travel, but the Doctor puts her mind at rest, saying he sees them too (with a smile that wasn’t half reminiscent of Tom Baker!). Then three lights circle a man by himself and suck him through the ice which then refreezes. Following which a couple of street urchins steal the Doctor’s sonic screwdriver. More lights follow the boy and suck him under.
Bill is upset by the boy’s death. It’s the first time she’s seen someone actually die. She’s also upset with the Doctor. The Doctor says she can either help him help the other children, or be outraged. It seems the children are being paid to lure people onto the ice.
So, what exactly is under the ice, apparently eating people. The Doctor says that that they need to get a closer look. Bill isn’t too impressed by his proposed method. The big scaly monster is connected to someone else.
The Doctor shows how to handle a situation with tact, diplomacy and charm. With the sort of results you’d expect.
Some more about the mysterious vault and again there’s a problem with the music drowning out dialogue.