The Sinestran Kill (audio story)

 was the first story in the eighth series of The Fourth Doctor Adventures, produced by Big Finish Productions. It was written by Andrew Smith and featured Tom Baker as the Fourth Doctor and Jane Slavin as Ann Kelso.

Publisher's summary
When the Doctor decides to trace an anomalous energy signature on twentieth century Earth, he stumbles into an assassination attempt.

Gangland thugs are trying to murder a seemingly innocent shopkeeper, and it's only the intervention of the Doctor and Ann Kelso – a WPC who happens to be on the scene – that prevents a tragedy.

But why do the gangsters want the shopkeeper dead? And what does this have to do with alien technology?

The first stages of a grand conspiracy are about to be revealed. And finding the answers will take Ann Kelso on a journey like no other.

Part one
In London, 1978, WPC Ann Kelso goes to Tony Reynolds's shop and advises him to close early after known criminal Jimmy Lynch makes a brief visit. Jimmy informs his boss, Hugo Blake, of her presence in the shop but is told to complete his job regardless, Hugo telling him that he has "a little something" which will help. Meanwhile, the Doctor is building another K9 in the TARDIS when he receives a notification that a warped field damper is being used in 1978, three centuries before its invention, and decides to take a closer look.

With the shop closed, Ann attempts to call for backup but finds that neither her radio nor Tony's telephone will work. The TARDIS materialises outside and Ann goes to investigate, opening the door for the Doctor when he knocks. Jimmy breaks into the shop and attempts to kill Tony, but the Doctor flees with him and Ann into the TARDIS and determines that the warped field damper was behind Ann's inability to contact the police. After Jimmy flees due to the sound of sirens, the Doctor and Ann exit the TARDIS with the unconscious Tony and speak with DCI Neilson.

Jimmy explains to Hugo what happened and leaves with him. The Doctor searches the shop for the damper and realises that it must have been projected from elsewhere. He uses his UNIT credentials to avoid being taken for questioning by DCI Neilson and is recognised by him as "that Doctor" when he sees his TARDIS, after which DCI Neilson allows him to leave whilst Tony goes to stay at Ann's flat. The Doctor leaves in his TARDIS, leaving Ann bemused.

Jimmy and Hugo go to Kathy Blake who orders them to find another way to kill Tony, saying that they would not be safe until he was dead. Meanwhile, Ann goes to her flat with Tony and DCI Neilson, who leaves to arrange a proper safehouse and, in his car, requests a background check on Tony. The Doctor visits Kathy and Hugo and accuses him of being an alien in possession of the warped field damper before realising that he is simply fat of face and not in disguise. He does, however, tell the pair that he will stop whatever they are up to.

Ann leaves her flat to get fish and chips for Tony, telling him that she will be back in ten minutes. The Doctor is picked up by DCI Neilson, who heard that he had visited the Blakes and wanted to know why. He tells an unsurprised Doctor that Tony does not have any sort of past and that he is going to take him in for questioning, warning the Doctor to keep away from the case to avoid jeopardising it. Upon returning to her flat, Ann finds that Tony has disappeared and goes to his shop, finding him searching for something there. The Doctor appears, holding the encrypted microparticle multibank communicator that Tony was looking for.

Hugo gets a call from Frankie the Shiv telling him that he saw Tony return to the shop. Hugo and Jimmy leave with technologically advanced guns to make sure the job is done properly.

Caught out by the Doctor, Tony confesses that his real name is Trenix and that he has been put into witness protection by the Lawkeepers of Pandrin V after testifying against the Sinestrans, criminals who use empathic Lemurans to make others kill their victims. Hugo and Jimmy arrive with Ray Lennon, Benny Malone and Frankie and laugh off the Doctor's claims that they are being controlled. They are, however, surprised to find that they have been conditioned to see the Sinestran killrods that they are carrying as ordinary revolvers. The Doctor takes one from them and shoots Trenix, saying that there is no other way.

Part two
Being shot by the Doctor transforms Trenix into his natural, insectoid form, frightening the gangsters and causing them to flee in terror. They reason that they must have been drugged or deceived and head back to gather more men in order to kill their target. Meanwhile, the Doctor explains to Ann that he had set the killrod to stun and shot at Trenix to interfere with his DNA coder and is impressed by her practicality and open-mindedness. Ann is told over her radio that DCI Neilson wants Trenix taken to the police station to be kept in protective custody whilst Hugo is arrested.

Hugo tells the unbelieving Kathy about Trenix's transformation and begins breaking his conditioning, asking why they had to kill Trenix and whether or not they actually knew him. Kathy does so too and becomes able to see the killrods, after which Jimmy shoots Ray, Benny and Frankie and reveals that he is actually a Lemuran named Spandrin who took control of the body of Jimmy months prior. He influences Kathy into killing Hugo before killing her himself.

Ann takes the Doctor and Trenix to Scotland Yard and the three are immediately taken to one side by DCI Neilson upon mentioning aliens in front of the other police officers. The Doctor tells DCI Neilson that he would be killed should he attempt to arrest Hugo. Meanwhile, Spandrin asks for and receives five Sinestran assassins and has them enter the carcasses of the gangsters. The Doctor suggests that they contact the Lawkeepers to take Trenix to safety, giving the Sinestrans no reason to remain on Earth. He also tells DCI Neilson to recall the policeman watching the Blake house, but he has his mind read by Spandrin before he can return.

Trenix sends a message out to the Lawkeepers requesting an extraction team and mentions to the Doctor that he had attempted to contact them some months prior without success. The Doctor is surprised and concerned by this. DCI Neilson tells the Doctor that one of his policemen has gone missing, that he is going with a special firearms team to the Blake house and that the Doctor is welcome to join them solely as an observer. All communication devices fail, signalling that the Sinestrans are near.

DCI Neilson and the Doctor find that the police officers in the station have been killed. Spandrin and the Sinestrans appear and DCI Neilson attempts to shoot them before finding that his gun is out of action due to a cordolaine signal. Trenix and Ann arrive and the Sinestrans prepare to fire at him, causing the Doctor to shout for the four of them to run into a lift. They escape to the canteen and are split up, with Ann going looking for DCI Neilson and Trenix whilst the Doctor uses his scarf to escape from the building to enact his plan to defeat Spandrin and the Sinestrans. Ann attempts to distract them but they spot the Doctor and shoot at his scarf, causing him to fall.

Ann runs away from the Sinestran wearing Kathy and is passed a killrod by DCI Neilson which she uses to kill her pursuer. The two police officers meet up with Trenix and continue to climb the floors before hiding inside the Anti-Terrorism Unit, protected by its steel door. The Sinestrans begin firing at the door when the Doctor appears and lowers a ladder for the humans and Trenix to get to the roof where his TARDIS now stands.

The Doctor invites Spandrin onto the roof and asks about the truth of what is going on, surmising that Trenix had been a mercenary for the Sinestrans and that their attempts to kill him were for more than just revenge. Spandrin tells him that the Sinestrans have formed an alliance with an intergalactic group who once employed Trenix and want him out of the way. The Doctor presents the Sinestran assassins' bodies, threatening to keep them in an artron field until they leave and causing the Sinestrans to turn against Spandrin. Trenix removes his DNA coder and has his body taken over by Spandrin, who is then shot and killed by the Sinestrans. Unable to return to their masters, the Doctor tells them that a justice planet is the best place for them and they are arrested by Ann.

The Doctor returns to Ann in the TARDIS, having returned the Sinestrans to their own bodies and brought them to justice. He tells Ann that the TARDIS is a time machine and allows her to see inside again, where she asks to join him to help investigate the intergalactic group. She throws the take-off switch before he can finish making his offer.

Cast

 * The Doctor - Tom Baker
 * Ann Kelso - Jane Slavin
 * Hugo Blake - Ewan Bailey
 * Jimmy Lynch - Nicholas Khan
 * Tony Reynolds - Leon Williams
 * DCI Scott Neilson - Frank Skinner
 * Kathy Blake - Glynis Barber

Uncredited Cast

 * Policeman - Nicholas Briggs

Worldbuilding

 * The Doctor tracks the use of a warped field damper, which is 300 years too early for 1978.
 * DCI Neilson runs the Gang Squad.
 * The Blake gang includes Ray Lennon, Benny Malone and Frankie the Shiv.
 * Tony owns Reynolds Hardware, located at 282 Morgan Street.
 * The Doctor looks up Hugo in the Yellow Pages.
 * A DNA coder transforms DNA, making it perfect for disguise. It can be disrupted by a stun gun.
 * Ann is WPC 166, which the Doctor says are his three lucky numbers.
 * Neilson was in Special Branch for five years.
 * The Sinestrans use a cordolaine signal, which the Doctor notes is a Sontaran invention.

Continuity

 * The Doctor is again believed to be a Time Agent. (TV: The Talons of Weng-Chiang)
 * The Doctor is working on assembling K9 Mark II in his box, (TV: The Invasion of Time) and learns his brain is positioned "arrow A to the front." (TV: Destiny of the Daleks)
 * The cordolaine signal is associated with the Sontarans. (TV: The Sontaran Stratagem/The Poison Sky)