‘Tui!’ I shout, an irritated edge creeping into my voice. It’s not her fault, I think, checking myself. I’m just grumpy because of the jetlag, and the pain in my ankle, and the fact that Kit appears to have staged a vanishing act. If only he’d reply to my messages.

‘Tui, where are you?’ I call again, pushing branches out of the way. As I emerge from the treeline, however, I freeze.

There are silver balloons tied to the bushes. Not just a few, but hundreds, each one trailing a gold ribbon. My first thought is that this must be a child’s party my intrepid sister has stumbled upon. Not a lot comes between Tui and cake – certainly not something as flimsy as a non-invite.

When I venture further, however, taking care on the sloping ground, I find no trace of a party, just more balloons. They seem to be leading all the way down to the jetty, so I follow, calling out Tui’s name as I go. It is only when I can see the upturned husks of the rowing boats that I spot my errant sister – and she’s not alone.

Kit is standing about halfway along the wooden jetty, his open palms facing forwards and a lopsided smile on his face. It is so good to see him there that I almost run to him, but my mystification – and my ankle – holds me in place.

Tui is crouched in front of him, Beavis in her arms and an expression of such glee on her face that it makes me laugh.

‘What is going on?’ I ask. ‘It’s not my birthday for months.’

Kit doesn’t reply. Instead, he glances down at Tui. ‘I knew this little monkey wouldn’t let me down,’ he says. ‘Swore her to secrecy, but as you know, sometimes she can’t help but spill the beans.’

‘Jeeeez!’ Tui retorts, laughing.

‘Why all the cloak and dagger stuff?’ I call, taking a few steps forward before Kit raises a hand to stop me.

‘You’ll see,’ he says. ‘Now, Tui, do me a favour and go and wait over there, yeah? Sit your bottom down on the bench.’