How long is 73 yards?

Haunted by a sinister presence, Ruby must cope with losing the Doctor and the life she once knew. With her new life without her best friend becoming bleaker by the day, something terrifying is unleashed, and it’s up to Ruby to stop it.

This eerie episode from Russell T Davies is novelised by series script editor Scott Handcock, featuring the Fifteenth Doctor played by Ncuti Gatwa and Ruby Sunday played by Millie Gibson.