When we last left the Doctor and Clara in Under the Lake they had become part of a ghostly encounter in the underwater mining facility the Drum. After the Doctor deciphered the message that each of the ghosts were mouthing, he set off in the TARDIS to 150 years previously to discover the source of the situation. Meanwhile as Clara and the remaining crew members stayed in the year 2119, a new ghost suddenly appeared - the Doctor himself. Now the story splits into two different time periods for the conclusion of the latest Doctor Who adventure from writer Toby Whithouse - Before the Flood.