Doctor Who Unbound

Doctor Who Unbound was a series produced by Big Finish Productions. It featured hypothetical stories set in variants of the Doctor Who universe with premises fundamentally altered. These premises were often built upon "what if" propositions such as; "what if the Doctor hadn't left Gallifrey" (Auld Mortality), "what if the Doctor hadn't been UNIT's scientific advisor?" (Sympathy for the Devil) and "what if the Valeyard had won" (He Jests at Scars...). Others like Full Fathom Five's story was more vague built upon the idea of "what if the Doctor believed the ends justified the means?", while Deadline takes on the more meta-textual premise of "what if Doctor Who had never existed?" The final story in the ongoing series, Exile, featured a female Doctor, an idea that has been raised several times throughout Doctor Who's production. Each one featured a Doctor created specifically for the series, aside from He Jests at Scars, which featured the Valeyard.

First released in 2003, the first series of six Unbound stories were part of Big Finish's celebration of the 40th anniversary year of Doctor Who. Two subsequent stories were released in later years: the 2005 story A Storm of Angels was a sequel to Auld Mortality, and the 2008 story Masters of War  was a sequel to Sympathy for the Devil.

In 2016, the Sympathy for the Devil version of the Doctor and the Master returned for The New Adventures of Bernice Summerfield Series 3, The Unbound Universe in which Benny, a companion to the mainstream Doctors, crossed over into the parallel world of the Unbound Third Doctor, finding it devastated by a cosmic war, akin to the Last Great Time War but without the clear conclusion. By this point in the Doctor's life, all reality had been brought to the brink, but was barely saved by him at the last moments in a way he couldn't remember. Still facing imminent collapse and bearing open battle wounds, this universe is a difficult place for Benny to adjust to when compared to N-Space.

Other usage of the term
Aside from stories officially released under the Doctor Who Unbound range, the "unbound" term has been adopted as a general descriptor of out-of-continuity stories. Paul Cornell, writer of Scream of the Shalka (which was retroactively subsumed in continuity by the BBC Wales Doctor Who series) has since referred to that story as his "unbound." Nicholas Briggs has also informally described certain stories in Big Finish's Sherlock Holmes range which don't fit into its general continuity as "Sherlock Holmes Unbound."