Intervention Earth ( audio story ) Intervention Earth was a standalone release following the sixth series of Big Finish ' s " Gallifrey " audio series . It was the first release not to focus on the dynamic of Romana II , Leela and Narvin , and instead focuses on Romana III , Ace and Narvin . Additionally , the story marked Stephen Thorne ' s return to the role of Omega , whom he previously portrayed in TV : " The Three Doctors " in 1972 . Publisher ' s summary . Times change . . . Romana is approaching her final term of office , and hopes to leave her world in a state of peace and harmony . Narvin is concerned about the implementation of a controversial Precog programme , one that seeks to predict the Time Lord s ' future . Ace is an operative for the Celestial Intervention Agency , having learned the art of interference from one of the best . . . And somewhere , across the stars , an ancient force is stirring : one of the Time Lords ' greatest heroes is returning to our universe . But he may also prove to be their greatest threat . When the history of Earth is threatened , and an ancient conspiracy reaches the heart of Time Lord government , can even Romana ' s closest allies truly be trusted ? Time will tell . . . but by then , it may already be too late . Plot . Part one . On a CIA mission , Ace returns to her TARDIS to find the presence of Rexx , who has been assigned to Ace by the High Council . He explains that events are spiralling out of the Time Lord s ' control and that the universe is in jeapordy . He relays a message from Romana , which explains that a black hole in Mutter ' s Spiral is growing exponentially , draining energy from the universe and threatens to warp established history - and the Time Lords themselves . On Gallifrey , Merkis speaks to Narvin converned over the precogs , beings who can predict the future introduced by Tauras in Romana ' s absence . The precogs repeat a myriad of voices : " He is returning . " The precogs have predicting the fall of Gallifrey within every reality , causing the walls between universes to collapse and placing the timelines in flux . Narvin requests access to President Romana , and meets with her in her private rooms despite Lukas ' refusal . Romana believes the Time Lords should observe the universe rather than interfere , despite the actions of her previous incarnations . Narvin sees this as suicide , but she believes it is the only option with the threat of the fall of Gallifrey as predicted by the precogs ; she cannot interfere with the anomaly as it would affect public perception of her . Narvin mentions that the CIA produced a presidential writ to give them power in which to interfere with the anomaly . Romana believes the anomaly should be analysed further before it is dealt with , and suggests if a malevolent force is behind it , they should be eliminated from the timelines . Ace ' s TARDIS materialises on an atmosphereless , primitive and derelict Earth , devoured by the anomaly and burnt out by the sun prematurely in 2015 . Ace is taken aback by how beautiful the dead world is . Rexx theorises the anomaly has been engineered , given its coordinates . Ace hears a cacophany of abstract voices , echoes from alternative universes , which gives her a migraine . Rexx tells her she is not a true Time Lord and that the Time Lords are used to these phenomena . Realising everyone she knew is dead , Rexx explains that they are there to find a relic that should have never left Gallifrey ' s arsenals - the Hand of Omega . Merkis informs Narvin that they have located the source of the anomaly , Earth , and the origin of the energy signature - the Gallifreyan armouries . Narvin leaves to inform the High Council . Ace and Rexx locate the Hand of Omega , explaining it cannot be stopped but should be moved into her TARDIS . She is able to operate it because of her previous encounter with it . However , the cloister bell is activated , and Rexx warns her they only have a minute before it threatens to destroy Earth . Ace and Rexx hear more voices from the past and future , indicating all timelines are bleeding into one another . Locking her TARDIS , Rexx tells her she must travel to the source of the anomaly in 2986 BC . Amongst the cacophany of voices , Omega ' s voice is heard : " I will return ! " Tracing the time distortion to Greater Henge in a storm , Ace explains no - one understands its origins . Suddenly , Rexx raises a gun to Ace , explaining he embellished the truth , manipulating her relationship with Mutter ' s Spiral and in spite of the privileges handed to Ace by Romana . Rexx wants to restore Gallifrey to its former glory by deploying the Hand of Omega , removing its off - world " traitors " and securing its future . Having used Ace to open the Hand , he stuns her , in joy over Omega ' s return . . . " to be added " Part two . " to be added " Part three . " to be added " Part four . " to be added "