“I thought you were going to drown,” she confesses. “I saw you go under – I didn’t know if I could… ” Her arms squeeze him in a fierce tight hug.

“I wanted to show you. I thought I could do it.” The tears are spilling out again. He keeps his head against her chest. Maybe she hasn’t noticed.

“It wasn’t your fault,” she says. “It was the undertow. It’s really dangerous, there are signs everywhere. I don’t know why Mum and Dad didn’t stop you.”

“I said I was going to get seaweed,” he whispers.

Suddenly she smiles at him.

“You nearly had it, you know.” She pats his back. “You were nearly doing it! You just need to practice in that awful – that ace pool thing. I’ll make sure you can do it properly before you go back in the sea.”

“Let’s go back,” he says, and she nods fervently. Her hold on his hand is tighter than usual.

Their parents have barely moved. Their mother gleams brown and beautiful on her towel. On the lilo, their father’s face and chest are turning red.

“Shall we not tell them?” he says suddenly.

She stares at their clasped palms. “You’ve got hair all in your hand.” She picks out tangled brown strands from between his fingers. He wonders where it came from.

“So, shall we not tell them?” he repeats.

She looks at their parents, oblivious and calm, and then back down at him. He wonders what she’s thinking.

“Why did Mum and Dad let you go down there on your own?” She wipes her nose with the back of her hand. “Why weren’t they with you?”

He shrugs. “You know what they’re like.”

She looks at him for a long time. He can see something changing in her, something deep and fundamental that squares her shoulders and lifts her chin.

“You stay with me from now on, okay? If you want to go swimming, come with me. And don’t let them take you down to the caves, not today. If they try and make you, just say you want to build something instead. We’ll go tomorrow morning if you want to see them.”

“But can we not tell them? About… ”

“Promise about the caves?”

“I promise.”

“Then we won’t tell them,” she decides.

“And you won’t tell them I cried?”

She touches the skin beneath his eyes with a tentative finger. “They might notice.”

“We could say I fell over?”

“Okay. We won’t say anything to start with, but if they notice, we’ll say that.”

Suddenly the whole episode takes on the dimensions of a tremendous adventure. He almost swam. His sister saved him. The day is magical once more. Overwhelmed by an irresistible impulse, he pulls her head down so he can kiss her.

“I love you,” he confesses.

Her face remains close to his. He can see the freckles on her small straight nose, her brown eyes that are the same shape as his but lighter, mid-brown where his are black. Her hair hangs over her shoulders in long salty ropes. Her hand tightly grasps his and her eyes well with tears.