Maori legends best paint an understanding of the close relationship between people, earth, sky and water. Rob loved stories about the taniwha, colossal beings of the sea, gods and monsters made of strength, sinew and spine, sometimes benign when acting as protective guardians, sometimes destructive when tossing people down their gullets like oysters.

When he was in New Zealand shortly before he died, he mentioned taniwha in one of his emails. I liked to hear about the details of his day.

Aotea (aka Great Barrier, I am trying to get used to the Maori names for stuff we never used the Maori names for when we were kids) was visible on the horizon as the sun came up, but there was rain coming up from the south, so Hauturu (Little Barrier) was hidden away. I have an image at the moment of Hauturu as a ginormous taniwha in the shape of an octopus, slowly (and balefully, it would have to be balefully) opening its eyes, with the bush proving to be no more than the moss on its (baleful) brow. I imagined it moving slowly towards the harbour, stopping to wrap a ginormous tentacle around the crater of Rangitoto, pulling it into the sea, causing a tidal wave that would push the container ships up against the cliffs, the yachts in the marina up onto the motorway, send seawater frothing. I pictured people standing on Maungauika watching the taniwha follow the wave in and tear down the bridge, before generally eating people and making a menace of itself. Okay, it looked cooler in my head than it does written down.

Mythology says taniwha can live in the sea or dark caves, but they can also live in rivers. And some say that if a person had dealings with one when they were alive, they may transform into a taniwha when they pass away. I love the idea of a person’s soul pouring into a creature of seawater, moving amid the depths of the ocean, gliding over underwater forests of coral.

A hundred taniwha are meant to live in the Waikato, which is New Zealand’s longest river, each one representing a great Maori chief. As rivers go, it is a powerful spiritual link between the land of the living and the land of the dead.

Waikato begins its journey at Mount Ruapehu in the south, winds its way to Lake Taupo (the largest in New Zealand), and then empties into the Tasman Sea. Along its entire 425 kilometres, the speed and landscape can change from sedate water to thundering blue foam crashing over rocks.

Prue, David and I are at a café next to a calm part of the river, sipping the best cappuccino in the world. When driving south from Auckland, it’s a convenient stop. The reason why it’s the best isn’t because they use Allpress or beans harvested under the light of a full moon. It’s because when I close my eyes and feel a little burst of sweetness as the chocolate dust hits my tongue, I imagine Rob next to me, as he was almost exactly three years ago.

It’s not sadness, rather an imprint of a time and place before I knew the full truth about what was happening with him.

We were all on our way south to Waitomo to look at glowworms, and he made fun of Prue in the gift shop. ‘You’re never going to buy anything, Mum,’ he hollered as she pottered around the merino slipper section, while David looked patiently on, having done this dance many times before.

Now, we are on our way south this time to Rotorua, to the land of sulphur and hot springs. We will always be three, never again four.

Although I feel Rob’s absence, I wonder if he is a beautiful taniwha, taking a break from swimming with kingfish and thinking about who to eat, and is watching us from the rushes of grass below our window.

If Rob is a taniwha, I wonder if he thinks about the only time we visited New Zealand together.