How did you research the story?

It was huge fun. I read lots of books and researched on the internet as I wrote. Then I visited the Natural History Museum and took a tour behind the scenes where I saw the actual specimens collected on the Beagle. I went to Downe House, where Darwin lived for most of his life, and stood in Darwin’s study, then I spoke to some amazing experts who described Darwin’s life after the Beagle. I visited Chislehurst Caves and some caves in Portugal to inspire the underground scenes. I watched David Attenborough’s wondrous Galapagos TV series many times. And I read Charles Darwin’s The Voyage of the Beagle. I observed, and gently handled, lizards at a reptile sanctuary, to watch their behavior and movement, and visited Marwell Zoo and London Zoo.

How much of the story is true?

I’ve tried to keep it as accurate as possible—the equipment, the boat, and the settings. Everything outside of Darwin’s interactions with Syms, the lizards, and Queen Victoria actually happened.

I also added in historical facts I discovered in my research. Darwin really was very seasick and hated the sight of blood, which stopped him from becoming a doctor. He did have a homemade eyeglass like the one in this story—I saw it on display at his home, Downe House. And he really did ride a giant Galapagos tortoise.

Syms Covington and Farthing have a very special bond. Did you have any pets growing up?

My first pet, at age nine, was Chestnut the hamster, who lived to nearly four years old—over one hundred in hamster years! Then we had Baggins, the African gray parrot, who used to soak his seeds and titbits in water, throw them at me from his cage, and shout my name in my dad’s voice. Now I have my two cats, brother and sister, Buster and Flinty, who fill my house with fluff and cuddles, fight over who can leave the most fur on my desk chair, and tell meowing tales on each other.

Tell us about the dragons …

My instinct is always to try to make things as believable as I can, with lots of science involved. The world is so full of weird and wonderful creatures, so I took all my inspiration from nature and started by researching those flying prehistoric giants, the pterosaurs, and studying the behavior of other dinosaurs. I gave my dragons a very strange life cycle, stolen from creatures like frogs and butterflies, which go through a metamorphosis—the features of their body changing as they grow. I combined this with the ability to survive over very long periods, like the Greenland shark, which can live to five hundred years old.

I hope that I have made breathing fire seem real. Because why not? Animals have evolved many defenses that seem magical, from stings and bites, to spitting venom and acid, to electrocution. All fire needs is a spark, fuel, and oxygen. I invented a dragon with sharp plates in the back of its throat that could grind together to make a terrible scream, and friction that produces a spark. Then I gave my dragon a special chamber above its stomach to store flammable gases released by digestion, which would act as fuel. The spark meets the fuel and hits the oxygen in the air … Let there be fire!