Clarke’s novel accomplishes an ambitious task, stepping into the world of sibling love in a haunting thriller that crosses the oceans. Mia Greene is found dead, her body discovered at the bottom of a cliff in Umanuk, Bali. The police believe that there are no suspicious circumstances. Mia was on a world trip, a loose route begun on the west coast of America and in Western Australia and supposed to have taken in New Zealand.

As Mia’s body is repatriated back to the United Kingdom, older sister Katie is unable to comprehend the shock of losing her sister. She can’t even begin tell her fiancé, Ed, about the terrible argument she had with Mia and the hateful, shameful things she said just before Mia left on the plane with Finn, her childhood best friend. Anger and hurt have been festering for months, but as Katie’s instincts begin to outweigh the shock, her thoughts continually lead her back to the last time she hugged Mia goodbye at Heathrow airport.

After Mia’s funeral and an angry confrontation with Finn that he didn’t do more to protect her sister, Katie is left alone only to find her worst fears borne out. She’s sure there’s something that the authorities have missed that would prove Mia died for a reason other than suicide. What the Internet, the witnesses, and the Balinese police don’t know is that her sister would never had jumped. Initially hesitating, Katie abruptly decides to retrace her doomed sister’s steps, complete with Mia’s backpack and her sea-blue journal holding the record of her journey. The journal holds the most intimate details of Mia’s thoughts, which perhaps hold vital clues to her fate.

While there is no real notion of tangible danger, Clarke’s unique talent is her portrayal of the fluid, quixotic and dark relationship between Mia and Katie. Alternating between Katie and Mia’s voices, Clarke intersperses the issues that have shaped Katie and Mia’s life until now: their mother’s sudden death from cancer; the unexplained abandonment of their father, Mick, who now lives in Maui and has kept a devastating family secret; and the wall between Katie and Finn that is stacked with “hard bricks of resentment” and cemented by Mia’s silence.

Foster builds on Katie’s uneasiness as she travels to Maui to reconnect with Mick, then to Western Australia and on to Bali, where she follows the aura of secrecy that pervaded Mia's time there, from the day she landed to her precipitous fall from the Umanuk cliffs. Not knowing what to believe and refusing to countenance Finn, Katie’s fingertips skim the edges of Mia’s diary to her final entry and a series of illustrations that portray a reckless, unpredictable girl who swings from energetic reckless highs to crushingly troubled lows.

The settings adds as much piquancy to the novel as the drama of the sibling relationship--especially Bali, where the air smells of clove cigarettes, fried fish, and motorbike fumes, a landscape that seduces both the sisters. As Kate’s journey turns strained with regret and a weariness that spreads through her body like the heat, snippets of information are gleaned: from Finn, who holds a silent flame for Mia; sexy surfer Noah, who imprisons Mia in a cauldron of passion; and also Ed, who becomes more distant and duplicitous as the story unfolds.

Untangling a web of passion and deceit, the word “suicide” flutters like a moth in Katie’s thoughts as she reads in Mia’s journal of an intimacy shared on a single sleeping bag that changed the shape of a friendship. Part of Katie’s journey is to finally understand the depth of Mia’s anger at her, and to finally glimpse into the life of a little girl lost and two very different sisters in desperate need of comfort.