The story sees the return of the Mara and a new alien race, which Tegan must fight without the Doctor’s help.

“In Tom Baker’s last story, Tegan’s Aunt Vanessa says to her niece, ‘Your father’s farm is hardly the Outback dear’.

“I’ve loved the beauty and drama of Queensland’s sugar cane country ever since I was a kid. So that’s where I put the farm.

“At the end of the next series, Tegan gets left behind on Earth. She has unfinished business with the Mara, a villain that lives inside the mind but can manifest as a snake. There are plenty of dangerous snakes in the sugar cane fields of Queensland.”

Read the extract from Fielding’s story Little Did She Know…

When she kneels beside her father, she can’t feel a pulse, and he doesn’t seem to be breathing. Her air stewardess training kicks in. Ignoring the prickling in her right arm, she rolls her father on to his back, tips his head back, checks his airways are clear and begins chest compressions. If he dies now, before we’ve made peace with each other . . . Tegan can’t bear the thought of it. She tries to keep her mind on the immediate tasks of restarting his heart and his breathin.g

Her father has just eaten, so the danger of him choking on his own vomit is high, and she is thankful for the lights of the approaching water truck. Luke must have seen her because the truck’s engine starts idling. She can hear the urgency in his voice as he talks to Uncle Vince on the two- way radio, asking him to ring for an ambulance.

As well as the chest compressions, Tegan needs to get her father breathing again. When she turns her head to give him a couple of rescue breaths, she gets the most terrible shock. Not three metres away, an Eastern Brown snake is eyeballing her. Tegan freezes. Eastern Browns don’t normally go looking for humans, nor are they usually active at night. The fire must have chased it out of the cane field. Capable of striking multiple times and packing more than enough venom to kill both her and her father, it is responsible for more deaths in Australia than all other snakes combined. It is fast and aggressive when it feels threatened.

As the thought passes through her mind, the snake slithers forward into the pool of light from the water truck’s headlights. The prickling sensation in her arm intensifies. She knows she needs to restart chest compressions immediately if she is going to save her father’s life. However, if she moves at all, the Eastern Brown is likely to interpret it as aggression and strike at both her and her father. Once again, it is as though the snake can read her mind. It rears its head and flattens its neck, signalling it will strike.

She hears a voice inside her head.

‘Did you think I was finished with you?’ Then laughter. She knows that voice. It is the Mara. It has seized the opportunity to create terror by summoning the Eastern Brown and now it is feeding on the anguish the snake is causing her. Her father is dying in front of her, and she can’t move. She is responsible. She brought the Mara here. She doesn’t know what to do and can sense that the creature is drawing strength from her internal conflict.

The adrenaline coursing through her body stretches time. She focuses. She focuses harder than she has ever focused before and talks to the demon inside her head. ‘Kill me, and you kill your bridge to this physical world.’

More laughter. ‘Foolish Tegan. What makes you think you are my only target?’

Her eyes are still locked on to the Eastern Brown; all her senses are on high alert. She registers that the Triantiwontigong, lying to the left of the snake, has begun to glow faintly. She hears the water spraying stop and the clang of metal as her brother climbs down from the vehicle. ‘Uncle Vince is calling the ambulance,’ he says. His voice is close and calm. She doesn’t dare turn her head to look at him and risk causing the snake to strike.

Her right arm is now searingly painful. The air is full of the smell of burning cane. In the periphery of her vision, she sees Luke stomp on the ground, trying to distract the snake. Not Luke. Please not Luke. The thought passes through her head before she can stop it.

As the Eastern Brown turns towards her brother and opens its mouth to strike, the three strange lights reappear. Startled, the Eastern Brown strikes at Luke and then at the glowing Triantiwontigong. Before it can strike again, the snake is hit by three bright orange beams and slithers away at speed.

Tegan barely registers the lights disappearing again. She doesn’t notice until much later that they have taken the Triantiwontigong. She recommences CPR on her father and prays that the interruption has not been too long. Luke lies down on the ground and doesn’t move.

‘Did it get you?’ she asks her brother.

‘I think so.’ They both know the bite of an Eastern Brown is usually painless at first. ‘Guess I’ll know how bad it is soon enough.’

Tegan desperately wants to help her brother, but she can’t interrupt her father’s CPR again. ‘I’ve got to keep . . .’

‘Yeah, I know.’ All Luke can do is try to stay as still as he can. Even the movement involved in taking off his T- shirt and turning it into a compression bandage could increase the circulation of the venom in his body.

Off in the distance, they hear a fire engine.

Doctor Who: The Adventures Before will be released on 3rd October and is available for pre-order now