Sophia Holmes and the Empty Hearse (Sherlock's Daughter Fanfic) *Completed*

I take the short cab ride over to Westminster station and head down the steps before being waved on through by one of the ticket guards who must have been warned of my arrival. As I walk towards the platform, I step across to the right-hand side wall to let the crowds bustling for the next tube pass me as I crack open the lock of a maintenance entrance with a hairpin and slip inside.

I take out a torch from within my pocket to guide my way down the sequence of maintenance tunnels. In truth, I have no idea where I'm heading, but my best bet is to follow the sounds of the tubes that are rattling past once a minute.

The tunnels seem to go on forever as I head further and further down, through narrow tunnels and walkways and climbing down steep metal ladders. Eventually, I reach another maintenance entrance and open that one to get me out onto the stairs leading down to the Sumatra platform.

It's so eerie down here - the platform is in complete darkness and is closed off behind me. I suddenly get the feeling of how far underground I am, and how there is probably little chance in me getting back out to the surface again if I can't deactivate the bomb.

But saying that, I can't even see where it is. I had expected the car to be waiting by the platform so that Moran could have stepped off from it and onto the platform, but it's not here. Perhaps I've miscalculated and it's somewhere else.

I close my eyes and try to envisage where I am. The platform itself wouldn't be directly under Parliament because the station entrance would need to be easily accessible to the public, and so that puts me a little way up the road. In that case, Parliament would be to my left and therefore it would make sense that the car is over there too.

I hop down onto the tracks, making sure to avoid the live rails as I start walking down the tunnel. There should be a vent in the ceiling somewhere for the heat to escape through, and that can't be too far away.

Sure enough, as I walk around a gentle bend, I see the car hidden. I look up at the large vent above me and see the walls lined with tens of small demolition charges.

Not sure how much time I have left, I peer under the car to check for the bomb to no avail before climbing in through the driver's door to get in. As the door shuts behind me, I duck down as I see two beams of light coming steadily towards me from the way I just came. They took their time.

"Ah. Look at that," I hear John say as he rounds the corner, then watch as they both spot the demolition charges on the wall above.

I reopen the door and lean out. "You made it then," I say, making them both jump.

"Sophie?" John says, breathing quickly. "Please say you've called the police."

"Nah," I lie, "I thought you'd be with them."

"Oh for-" John says, whipping around angrily and looking at dad. As he looks back, he calms. "Right, well let's find this bomb then."

I swing back out of the way to let them get up, not making eye contact with dad as he passes me. We walk slowly through into the compartment, looking at every seat, every corner, shining our torches along the ceiling and the floor. At the second set of side doors, dad slows down, paying particular attention to something as John progresses on to the very end.

"It's empty," John says. "There's nothing."

I walk over to where dad was looking and see a pair of intertwined black and red cables strung along the wall and down to one of the seat backs.

"Isn't there?" he says, and John turns back and points his torch where dad is gently lifting the cushion, bending low to shine his light underneath. Dad lifts his head and looks round at him. "This is the bomb."