‘You’re good to go,’ he told me, patting my back which made a dull clanging sound on the air tank. It made the hairs rise on my neck. Of course, I was technically good to go. But what if I panicked? What if I forgot to breathe? There were so many things that could go wrong. Arterial gas embolism, where a nitrogen bubble trapped in the bloodstream travels to the heart and causes it to stop beating. Decompression sickness, better known as the bends, where a too-fast ascent results in a reduction in pressure, causing nitrogen bubbles to fill the body’s blood tissues. At its worst, it could end in nerve damage or even death. Then there’s nitrogen narcosis, a condition only experienced when diving at certain depths. Divers have all sorts of names for it: the Champagne Giggles, Nitrogen Euphoria, the Raptures of the Deep. I’d experienced it a few times – all divers inevitably would if they dived often, as I had in my twenties.

Symptoms vary between divers. Some people get all turned around, no longer able to tell up from down, or right from left. Others hallucinate, offering their regulator mouthpiece to fish or turtles. They have trouble concentrating, become confused and distracted, make rash, impulsive decisions like entering wrecks or caves without checking first to see if they’re safe. In my case, the narcosis had infused me with a warm sense of peace, the kind I had been searching for all my life. There was only one time I was ever in real danger. Diving a wreck near the Philipines I’d imagined someone was following me, convinced that each time I turned around, the person disappeared behind a rotting timber beam. I drifted further and further from my dive group, searching the cabins for the mysterious person who was taunting me. I started to grow angry. Grabbing hold of a column, I managed to cut my hand on a sharp bit of metal. Blood clouded the water instantly. I watched its progress impassively, with only the mildest curiosity. There was no pain, only a dull sense of disappointment. Thankfully, another member of the group noticed my odd behaviour. They hauled me up and we returned to the surface safely.

Ahead of us, Emerens Ericsson’s yacht glided gracefully along the waves, a bubbling foam churning in its wake. Bram had given Emerens the coordinates for the dive site, which lay quite close to a sheltered beach just around the south-west headland, about a ten-minute ride away.