@pnwfan

If you watch from the start of the series (The Pilot), then you’ll know who the bald guy is (Nardole- he did appear previously in the last two Xmas specials) and why the Doctor is staying on Earth. I don’t want to say more for reasons of spoilers. You’re posting on an month-old episode. More is known at the currently aired point in the series.

@pnwfan

All will be revealed.