Smile The Doctor whisks Bill off to the far future to one of the first human colonies, but all they find are empty corridors and robots that communicate in 'emoji'. As the travellers delve into the mystery, they discover their only hope of survival is to smile. Thin Ice London, 1814. The Doctor and Bill arrive by accident at the last of the great frost fairs on the River Thames. Before Bill can enjoy the past, revellers are pulled beneath the ice and the Doctor must find out what lurks in the dark depths of the river... Knock Knock Bill rents a house with some friends, but on their first evening there, strange noises are heard. The house harbours a dark secret, and the Doctor would like a word with the eccentric old Landlord...