The night seems somewhat breathless. The steady trade wind blows on from the north east; the ship's bell is struck; the Wild Cat's canvas fills above them, grey against the night sky; a bright, impossibly distant swirl of hot tropical stars spins slowly above them. There is a change in the night. Susan, walking up and down the deck with Peggy, feels it, and exults in it. Her skin is sticky with tropical sweat.

Titty and Roger are on the other side of the deckhouse. She should send them to bed, but she doesn't, not yet. She can see a shadow that might be Bill, far out there against the stars at the very tip of the bowsprit. She should tell him to get back, as they're not picking him out of the Atlantic a second time, but she doesn't. She can smell the smoke of Peter Duck's pipe as he leans out over the bulwark to windward. Behind her, she knows Captain Flint is in the deckhouse, and John and Nancy are sharing the wheel again. She can hear the murmur of their two voices together; her brother's familiar voice is just too low to make out individual words, and even Nancy's clear, authoritative tones seem somehow muted tonight, although her ringing laughter is still as loud as ever. She hears John laugh too, and then there's a hurried silence as Captain Flint bangs open the deckhouse door and asks for a compass bearing, and tells Nancy that it's her watch below.

And Peggy, dear Peggy, is chattering away beside her.

She feels a sudden surge of affection for the younger Blackett sister, who has all of Nancy's cheerfulness but none of Nancy's headstrong passions and unpredictability; the same unpredictability that she knows so thrills her brother. Nancy, it seems to Susan, almost delights in stirring things up and causing trouble: let's climb Kanchenjunga, let's stir up the Great Aunt, let's stay for supper even though we were meant to be back for tea, let's find the buried treasure and scotch Black Jake – and let others think of the consequences; let others think of making the supper and counting the stores and boiling the eggs and keeping Titty and Roger warm; let others tremble alone in their cabins after that horrendous close shave with Black Jake in the fog…

Well, not quite alone. Peggy had come to find her then, as she always did.

Here comes Nancy now, striding round the deckhouse en route to the companionway and her bunk below. Her cheeks are flushed, her hair, under its cap, dampened dark with the sweltering heat.

'Good night, Susan. Good night, Peg,' she says as she strides past, tall and careless in the darkness.

'Night, Nance,' says Peggy, to her retreating back.

Peggy, always trailing and bobbing along in Nancy's gloriously carefree wake…

John, she knows, would give his life to be up there with Nancy at the very head of the wave, and Susan sometimes half-wishes she could join them… well, join Nancy, really; be swept up in the great jolly fun of it all… Susan, sweat cooling on her arms and legs in this breathless tropical night, ruefully admits to herself that sometimes she can't sleep at night for thoughts of Nancy Blackett.

But Nancy, Susan knows, is… well… out of reach. Nancy likes and admires John quite as much as her brother likes and admires Nancy. Girl meets boy. Boy meets girl. It's all painfully, coldly simple. It might as well be written in those blazing tropical stars. And Susan, sensible Susan, slams that particular book shut. Why waste time worrying if there's nothing you can do?

Peggy has stopped chattering. They've stopped at the front of the deckhouse. She looks at Peg, taking in the shirt, damp in patches with sweat; the bobbed brown hair under the red Blackett cap; the friendly brown eyes; the smile that could never be as broad or bold as Nancy's but tries its damnedest just the same, and doesn't half do a bad job… She's smiling now as she reaches out, quickly, and gives Susan's hand a quick, hot squeeze.

'What a lovely night,' Peggy says, and then looks a bit embarrassed.

Susan, heart contracting as her hand is squeezed, feels her old exultation return. Here she is, sensible Susan Walker, on the pale deck of this sea-going schooner, on the way to uncover buried treasure on unknown shores, under the blazing stars in this breathless tropical night, and here is Peggy, next to her.

'Yes,' says Susan, squeezing firmly back. 'Yes, it certainly is.'