New Peerlessness

New Peerlessness was a paradise prison planet the Time Lords built near Kasterborous. It was either contained within or connected to the Doctor's TARDIS, letting the Seventh Doctor through its shield because it knew him. This allowed him to trick the Shepherd and Shepherdess into living on "the most beautiful planet in existence," trapping them. (AUDIO: Persuasion)

The Shepherdess died there, and Will Arrowsmith later released the Shepherd thinking that he could help in stopping the Daleks on Azimuth. (AUDIO: Daleks Among Us)