Dot and bubble seemed to work as it was originally pitched back in 2009 for Matt Smith and Amy Pond by Steven Moffat but was left out due to budget costs and adding the Black Mirror light concept to the story helped make it work.
Is it me or is the Doctor a support character this series as the episodes seem to have a different main character for every episode with the Doctor just tying the stories together
Is it me or is the Doctor a support character this series as the episodes seem to have a different main character for every episode with the Doctor just tying the stories together