On the phone now, he is still talking about The King and I, describing how he first saw the film in Melbourne, in 1958. “All the boys I knew, they wanted to grow up to be Yul Brynner,” he says, laughing. Once, he had woken to the sight of his roommate practising his ballroom dancing, twirling an imaginary partner.

“And who did you imagine you might dance with?” Gail asks teasingly.

“I always danced with same person. In Sandakan, when I was young. But she died a long time ago. I thought I might see her again, but it was impossible.” She hears him shifting the phone to his other ear. “Don’t forget,” he says. “I want to surprise your mother. It’s been so long since we took a trip together.” When she puts down the phone, something in her mind seems to stop and catch, a word, a name, hovers on the edge of her memory.

The phone rings again, but she doesn’t pick it up. On the answering machine, Ansel’s voice. “It’s me.” A pause, and then he says, “Are you there? I didn’t want to wake you this morning before I left. Are you there, Gail? Anyway, that’s all right. It was nothing important. You looked so peaceful this morning. That’s all.” Something in his voice causes her to sit down, exhausted, unsure. “I love you.”

The message light on the machine begins to glow. She thinks of her mother, sitting at the kitchen table, polishing the glass beads of the chandelier, a task she did when Gail’s father was ill, when he slipped into a depression and she could not pull him back. Long ago, when she was a child, Gail would fall asleep in her mother’s lap, face pressed against the fabric of her dress. The familiar smell of soap and sweetness. Across the room, her father sat for hours in his armchair, his cup of tea gone cold, and it seemed to Gail that he had disappeared, cut himself loose from his body. Her mother would lift Gail from her lap, rise from her chair. She would place her hands on his shoulders, rubbing his neck and back. Touch calling another person back to this world, warmth flowing from one body into another.

A few months ago, she had helped her mother clean and organize her workroom. While her mother went to the kitchen to prepare lunch, Gail had got started, wiping the bookshelf. It was crammed with sewing manuals, but there were also cookbooks, magazines and novels: Balzac, Dickens, Thackeray, coated in a thin layer of dust. Gail had sat cross-legged on the floor, turning the worn pages. She was replacing the books on the shelf when she saw a handful of envelopes that must have fallen on the carpet. She recognized one of them immediately. It was addressed to her father, and the Dutch stamps, now yellowed and dry, curled up at the edges. She had slid the letter out, a single page, fragile and creased.

I am heartbroken to write that Ani passed away on November 29, 1992, at home, of cancer. Wideh has returned from Jakarta, and he is here now. He was with his mother at the end.

Before her death, Ani requested that I write to you, and she provided me with your last known address. I hope that this letter reaches you.

I am very sorry to have to write to you with this news.

The name at the bottom of the page was Sipke Vermeulen.

She goes back to her office. At her desk, she scans the list of sound files, trying to focus on her work. She chooses one and hits Play. The recording that emerges from the computer is her own voice, the interview with Jaarsma about cryptography and the Vigenère Square. “The ciphers leave a shadow,” Jaarsma says, in response to her question. “However faint, you cannot erase that. This is the narrow, almost invisible opening for the codebreaker. At Bletchley Park, during the Second World War, cryptographers often recognized a pattern they had seen weeks, even months ago. They would walk across the room, fish out the correct fragment from a stack of paper. As if it were all a dream. It was the subconscious memory of a pattern.”

In radio, in the countless scripts that she has written, Gail works with the belief that histories touch. Follow the undercurrent and you will arrive at the meeting place. So she weaves together interviews, narration, music and sound in the hope that stories will not be lost in the chaos of never touching one another, never overlapping in any true way. Each element a strand, and the story itself a work of design. Out of the disparate pieces, let something pure, something true, emerge. Let it remain there, visible.

And in this documentary, where is the truth in the story of William Sullivan?

Gail runs her pen along the script, making notes in the margin.

Years ago, in Prague, she had interviewed a woman whose teenaged son had drowned in the Vltava River, a tragic accident. In the midst of recalling that day, the woman had looked up at Gail, suddenly angry, asking why she dared to ask these questions, what right she had. Gail had opened the recorder, removed the cassette tape. She had placed it carefully in the older woman’s hand. “If only you could understand,” the woman had said, clutching the tape. “The words that I put in the world can never be taken back.”

She remembered the woman’s frantic gestures, the ribbon pulled out of the cassette, spooling onto the ground.

She opens a browser on her computer and begins to book her flight to Amsterdam. Dates, flights, times: the numbers swim before her eyes. When she has an itinerary ready, she prints it up, and emails a copy to Jaarsma.

Outside, a woman calls out, then a screen door opens and slowly closes, the hinges creaking. She types Sipke Vermeulen’s name into the computer and watches the results scroll down the screen. The Nederlands Fotomuseum in Rotterdam. World Press Photo. She follows a link, and a series of black-and-white photographs open up before her. The caption underneath reads, Algiers, 1959. The Algerian War.

For a long time she studies the photos. In one, a child plays on an abandoned tank, he hangs upside down, suspended from the barrel of the gun.

She opens one image after another, seeing images from the Netherlands, Germany, Indonesia, and it becomes clear that Sipke Vermeulen is a Dutch photojournalist, a war photographer.

Gail closes the browser, picks up the printed itinerary from her desk, and walks out of her office. She climbs the stairs to their attic bedroom. Standing at the window, she can see a dozen tai chi practitioners gathered in the nearby schoolyard, moving, out-of-phase, in a lengthening ballet. Elderly men and women flick their heels, stretch their arms away from their bodies, turn with a strange and gorgeous precision. Movement after movement unfolding, an outgoing tide, spreading towards the edges.

Many times in her childhood, she had woken to the sound of her father’s nightmares. A screaming in the dark, lights coming on in the house. She would creep to their bedroom door, holding on to the sound of her mother’s voice comforting him. Once, unable to go back to sleep, she had found her way, in the dark, to the living room. There, she lay on the carpet, her arms open, as if to gather up the air, to hold the weight of the room. From where she lay, she reached out and turned on the antique radio. The panel glowed and, after a few seconds, music, something jazzy, began to drift through the speakers. Eyes closed, she pressed her hand to the wooden cabinet, drew the vibrations through her fingertips, all the way to her heart.

When dawn came, she went to her parents’ bedroom, inched the door open, stood at the border of their room as they slept. She gazed at them with a boldness that she would not otherwise dare. Asleep, it was as if they had gone away together, leaving the worries of their life behind. She imagined casting a spell over them. When they woke, they would find themselves in a place where no secrets existed, where all the sorrows of the past had been laid to rest. What sorrows? She did not know. She knew so little about their lives. Privacy, her parents believed, was sacred.