The Agatha Oddly Casebook Collection: The Secret Key, Murder at the Museum and The Silver Serpent. Lena Jones

What does that mean? ‘Hydro’ is from the Greek for ‘water’. So, she studies water? Out of ideas, I go back to making sure she’s comfortable. I don’t risk moving her right arm, though it looks uncomfortable bent beneath her. But, as I fold my blazer and place it under her head, I spot something in her left hand. I don’t know how I missed it at first. With a glance at her peaceful face, I gently prise her fingers open to find a piece of folded pink newspaper – a page from the Financial Times. Looking around to see if anyone is watching, I open it out.

      It has the usual stories – mergers of electronics companies, CEOs getting millions of pounds in bonuses, a story about London pollution. Without thinking, I fold the paper and slip it into my blazer pocket. JP hasn’t returned yet, so I’m left alone to watch over the professor. Somewhere nearby, a siren starts wailing. I have an idea – opening my satchel, I take out a small brown bottle, unstopper it, and wave it under her nose.

      It was insanely difficult to find smelling salts in London chemists. Finally, a pharmacy on Old Compton Street had agreed to sell me some, on the condition that I leave my name and address.

      After a moment, the professor starts to take deeper breaths, and coughs twice. She opens her eyes and looks at me. The sound of the siren is much louder now, and I can see the ambulance racing across the lawns towards us, churning furrows into the dew-soft grass. Dad won’t be happy. It stops right next to us. The two paramedics jump out and start to tend to their patient.

      ‘What’s that you’ve got there?’ A paramedic points to the bottle I’m holding.

      ‘Sal volatile.’

      He looks blank.

      ‘Spirit of hartshorn?’

      ‘What?’

      I suspect the man of being a little slow.

      ‘Ammonium carbonate with lavender oil.’

      ‘Ah, aromatherapy. New age.’

      I sigh. ‘If you say so.’

      They check the woman’s pulse and breathing, and shine a light in her eyes to check for concussion. Then they apply a sling before loading her on to a stretcher. The one who called my smelling salts ‘new age’ asks me some questions about what happened.

      ‘Hit by a motorbike?’ He shares a look with his colleague. ‘She’s lucky not to be more seriously hurt.’

      ‘Pretty unlucky to get hit at this time of the day in a park, mind,’ says the other paramedic.

      ‘Luck has nothing to do with it,’ I say. ‘This was deliberate.’

      I give the paramedics my home address and say I’m happy to talk to the police. I think about offering to ride with the professor to the hospital, but before I get the chance the ambulance leaves, and I stand there feeling as though I’ve woken from a dream. But this was no dream, and when I reach into my blazer pocket – yes! – there it is – the folded sheet of newspaper.

      ‘Thank goodness for that,’ I breathe. There is a strange tingle behind my eyes. In the spotless blue sky above me, clouds are starting to form. Not just any clouds – they are spelling out words.

      The clouds form and dissolve away just as fast. My heart is racing. I pick up my satchel and start to walk, replaying the events in my mind, and several images refuse to fade.

      I think of the biker, whose face was hidden by the dark helmet. I think about the business cards from the Royal Geographical Society. And, most of all, I think about the key tattoo, in its silvery ink. I’ve never seen that symbol before. I pause – or have I? There’s something at the back of my mind, just niggling away at me …

      I stop, feeling frustrated.

      I’m already late for school, so surely it can wait another minute. I sit down on a park bench and open my satchel, taking out my current casebook. I’m so excited; it might as well be the first one – this is a new beginning. I flip open the notebook to the opening page and cross out the details about the local shopkeeper’s parking violations. I write the heading: ‘Hit-and-Run – Hyde Park’, underlining it a couple of times. Then I jot down some quick notes –

      1. Old lady knocked down in Hyde Park. The path was wide. Was this deliberate? What could the motive be?

      2. Her perfume was expensive, and she had an unusual tattoo (sketch overleaf). Something seems odd here – what is her story?

      3. Business card says she is a member of the Royal Geographical Society – do they know more about her?

      I look over all those exciting question marks for a moment, puzzling it over.

      Something is afoot, of that I am sure.

      ‘So, you saw an old lady knocked down in the park by a motorbike, and now you want us to investigate?’

      Liam is staring down at my notebook and frowning. We’re in form class, before lessons. ‘Don’t people get knocked down all the time? What makes this one any different?’

      I glance to the front. Mr Laskey is behind his desk, reading the newspaper, and it’s hard to tell whether he’s sleeping or not. The rest of 8C are chatting noisily, so there is little chance of our conversation being overheard. Still, there isn’t much time to tell Liam everything that has happened. Brianna Pike, one of the three CCs, is sitting on the desk next to us, but she’s too wrapped up with doing her make-up to pay us any attention.

      ‘Not just an old lady getting knocked down,’ I whisper. ‘There was something funny about it. This didn’t look like an accident. There were … unusual circumstances. Comprenez-vous?’

      ‘You mean –’ he glances around at our classmates before continuing in a whisper – ‘you think someone might have targeted her?’ He sounds more excited than normal about one of my cases.

      ‘Exactly! And if you come with me to the Royal Geographical Society, I’ll prove it to you.’ I hold out the professor’s business card.

      He takes it and reads. ‘Professor D’Oliveira, Senior Fellow, Hydrology Studiesd—’

      ‘We need to get going – now,’ I say, cutting him off. ‘Time is of the essence.’

      ‘Whoa, hold up! We’ve got school. What’s the hurry?’

      ‘I need to solve this before the police do.’

      ‘But we have a maths test! And you almost got expelled yesterday! Just wait till we’re finished.’ His voice is plaintive – Liam loves maths tests. He runs a hand through his hair, making it stick up at strange angles. I resist the urge to reach over and smooth it down. I catch the eye of two girls, who seem to be staring at Liam. That’s been happening a lot lately, since his growth spurt. They scowl at me and I shoot them a sweet smile as they start whispering to each other.

      I lower my voice. ‘I’m going now. Are you coming or not?’ I hiss. I draw my notebook back towards me across the desk and stare down at it, trying not to be influenced by the pleading look in his eyes.

      He sounds strained. ‘Erm … not.’

      ‘All right. But you can still help out with something.’

      He brightens. ‘What?’

      ‘On the woman’s wrist, there was a symbol.’

      ‘A symbol?’

      ‘Well, a tattoo. I feel like I’ve seen it somewhere before. I need you to find out what it means.’

      ‘Sure. What did it