The Sirens of Time (audio story)

The Sirens of Time is the first in the series of Doctor Who Doctor Who Audio Dramas produced by Big Finish Productions. Written and directed by Nicholas Briggs, the four-part story features the Fifth, Sixth and Seventh Doctors, with Peter Davison, Colin Baker, and Sylvester McCoy respectively reprising their roles from the original television series.

Publisher's summary
Gallifrey is in a state of crisis, facing destruction at the hands of an overwhelming enemy. And the Doctor is involved in three different incarnations - each caught up in a deadly adventure, scattered across time and space. The web of time is threatened - and someone wants the Doctor dead.

The three incarnations of the Doctor must join together to set time back on the right track - but in doing so, will they unleash a still greater threat?

Plot
to be added

Cast

 * The Fifth Doctor - Peter Davison
 * The Sixth Doctor - Colin Baker
 * The Seventh Doctor - Sylvester McCoy
 * Commander Raldeth / Schmidt - Andrew Fettes
 * Coordinator Vansell - Anthony Keetch
 * The President - Michael Wade
 * Elenya / Helen / Ellie / Knight Commander Lyena - Sarah Mowat
 * Ruthley - Maggie Stables
 * Sancroff - Colin McIntyre
 * Commandant / Lt Zentner / Pilot Azimendah / Sub-Commander Solanec - John Wadmore
 * Captain Walther Schwieger / Edifice Captain / Knight 2 - Mark Gatiss
 * The Temperon - Nicholas Briggs
 * Delegate - Nicholas Pegg

Astronomical objects

 * Calfadoria
 * The Kurgon Wonder was created as a result of the Knights of Velyshaa attempting to capture the Temperon.

The Doctor

 * The fifth, sixth and seventh incarnations of the Doctor make telepathic contact with one another to apprise one another of the situation through the spoken command "Contact".

Individuals

 * Tegan and Turlough are trapped within the Doctor's TARDIS when he arrives.
 * The Sixth Doctor mentions that he knows Hadene Lestrade.

Organisations

 * Coordinator Vansell is a member of the Celestial Intervention Agency.
 * The Galactic Wonders Commission decides which objects are Wonders of the Universe.

Races and species

 * The Knights of Velyshaa appear.
 * The Temperon is a legendary time beast. It is a 'cousin' to the Chronovores.

TARDIS

 * TARDISes have a time core.
 * Cloister Bell

Theories and concepts

 * The Laws of Time (supposedly) stop the Doctor's incarnations from meeting.

Sirens' altered timeline

 * The Fifth Doctor accidentally prevents the U-20 from sinking the RMS Lusitania in the Atlantic Ocean on 7 May 1915. This allows Eric Charles Vincent to kill Alexander Fleming before he discovered penicillin.

Continuity

 * The Fifth and Seventh Doctors previously met each other in MA: Cold Fusion and would later do so again prior to the events of BFA: The Veiled Leopard. The latter is not actually depicted but is witnessed by the former's companions Peri Brown and Erimem. Peri describes the Seventh Doctor as being "a kooky little guy in a weird pullover." She would later meet him more formally in NA: Bad Therapy.
 * The Sixth Doctor recalls climbing the Himalayas. (DW: Marco Polo)
 * The Knights of Velyshaa are mentioned and a Knight appears in BFDE: Invasion of the Daleks.
 * Vansell reappears in BFA: The Apocalypse Element and BFA: Neverland. Following his death in the latter story, alternative versions of Vansell appear in BFDWU: He Jests at Scars..., BFG: Reborn, BFG: Disassembled and BFG: Forever.
 * According to PDA: Instruments of Darkness, Evelyn Smythe was in the TARDIS while the Sixth Doctor was at the Kurgon Wonder.
 * The method through which the Doctors telepathically contact one other ("Contact") was first seen in DW: The Three Doctors.
 * Sancroff is mentioned by Kalendorf in BFDE: Dalek War: Chapter Four.

For the Fifth Doctor

 * This story occurs after ST: Lily
 * This story occurs before ST: Qualia

For the Sixth Doctor

 * This story occurs after BFA: The Marian Conspiracy
 * This story occurs before BFA: The Spectre of Lanyon Moor

For the Seventh Doctor

 * This story occurs after NA: The Room With No Doors (after the Doctor returns Penelope and Joel home)
 * This story occurs before PDA: Bullet Time