The episode ends with the Doctor showing Zoe his last encounter with the Daleks, to warn her of the dangers ahead if she choose to join the TARDIS. This was used to lead in to a repeat of the story "The Evil of the Daleks" the following week. Together with narration over the opening of that story, this uniquely tied the only repeat of a Doctor Who story in the 1960s into the ongoing plot-line.
In 2004 it was discovered that the footage re used from Evil Of the Daleks was not from the Opening of Episode 2 as had long been believed but due to the existence of a few extra frames of footage it was discovered to be from Episode 1 of that story, making it the only surviving clip from that episode as of 2019.
This episode takes place aboard Space Station W3 in the 21st Century.
This episode was watched by 6.5 million viewers on its original transmission.