Fire in the Sea Tour, Day 1: Cottesloe Beach

1. Cottesloe beach terraces

It was an afternoon like any other. The four of them, lazing on the terraces at Cottesloe beach. Kimberley arranged on a carefully laid-out towel, touching up her lip gloss. Her twin Heather, twenty-two minutes younger and twelve times as serious, turning over tarot cards. Tom sitting away from them, staring out across the glaring white sand.

Fire in the Sea opens at Cottesloe beach, a place where most of the best bits of my childhood were spent. It's a white sand beach, where the clear waters are calmed by a rocky groyne. On one side of the groyne, surfers wait for waves. On the other, children wade in warm shallows. During the summer, it's packed with tourists and suburban teenagers who walk up (and then down) the hill that separates the Cottesloe town centre from the beach. It's about a ten minute walk. People whose houses line that street campaigned to have the footpath moved away from their front fences and shoved up against the kerb, tired of the racket day-trippers make.

I always liked this beach because it was a miniature adventure playground. If you were young and tired of swimming, there were crabs to be found in the rocks of the groyne. If you were slightly older and reckless, you could dive from the rocks of the groyne into a narrow hole in the surrounding reef. (This was discouraged after someone broke their neck.) If you were even older than that, you could sunbake on the grass terraces and watch the younger kids enjoy themselves. Off the coast are speedboats and container ships, the latter queuing up to enter the harbour.

I wanted to open the book here for a couple of reasons. Mainly, it's a place that captures much of Perth's character: big skies, blue seas, heat and hedonism. But it's also somewhere that feels as if it's on the edge of the world. Sadie is as far as she can go, pressed up against the horizon. And every ship she sees waiting is a reminder of the outside world. The real world. Of course, she learns that home can be just as real, just as important and (in her case, at least) just as exciting.

2. The Reef

Sadie tightened the strap on her face-mask and dived in. She swam down along the edge of the reef, where curtains of kelp draped into the depths. Small silver fish sparked about her. The voices of the fishermen above dissolved beneath the comforting rumble of breakers.

I spent quite a bit of time snorkelling here in my teens. The reef is on the far side of the groyne and the water is a good deal colder, deeper and wilder. It was a great place to pretend you were Sean Connery, with a knife strapped to your calf. (My brother's knife, I never bothered to buy my own.) I never killed anything, certainly no sharks. Since I left, Perth has gone shark crazy. A combination of excessive fishing and the flushing of abbatoir by-products into the sea has lured white pointers closer to shore. I remember at least once, diving around sunset, that we glimpsed something in the water and pretty much ran across the waves back to the rocks. In that case, it was a dolphin. Other times, it might have been a playful seal, wanting to nip your flippers. In Sadie's case, it's something else entirely.

3. The Groyne

Sadie glanced down at her sandy feet, and when she looked up, a dozen of the Drowners were with them. Each standing on a rock, each with a gnarled hand to the barnacled hilt of their sword or axe-handle. With six on either side of the path, they formed a loose aisle, as if presenting themselves for inspection. Jake stood at one end and lightning flashed at the other.

A key scene takes place on the groyne — the first confrontation between Jake and Lysandra. It's a place I remember as being suitably dramatic. As soon as the wind picks up, large waves begin crashing over the groyne. When I was a child, there were power lines strung from poles along its path. They were blown down one too many times.

In Fire in the Sea, the groyne also functions as something of a threshold for Sadie. On one side, the quiet life she has. On the other, the promise of adventure and danger. From the start, she's ready to change sides.

3. The Path

Then, suddenly, there were two other figures on the grass. Neither Sadie nor Tom saw them arrive — they were, at once, just there. One knocked the man to his knees. The other grabbed him by the throat. Choking him.

The dramatic scene at the end of the first chapter takes place atop the same terraces on which Sadie and her friend have lazed away the day. The bike path runs from Fremantle harbour, all the way to the beach at Swanbourne. It's a track I've ridden along on BMXes and mountain bikes. In my twenties, I rollerbladed along it as a vague gesture towards exercise. In my thirties, I tried jogging along it. It's a lot longer than I remembered.

I don't remember exactly why I had Mr Freeman attacked here. It would have made more sense to have him attacked in the car park on the other side of the beach. I think I just liked the image of his attackers leaping across the vast green banks. I'm a very visual writer, I think. Maybe it comes from a day job reviewing films. I can't help wondering how each scene will work on screen. Clearly, we need to find someone to make the film version so I can find out.

Day 2: The Cottesloe Civic Centre