The body seemed to fall for a long time. There was no splash, or if there was it was lost in the waves. Isobel was frozen to the spot for a moment – and then her common sense caught up with her, and she stepped back quickly into the shadows.

When Isobel Petty is orphaned, she finds herself being taken away from her home in India and sent to live with a distant uncle in England. On board the S.S. Marianna, she witnesses a shocking act – somebody being thrown overboard in the middle in the night. But when the ship’s captain insists that nobody is missing, Isobel and her two new reluctant friends must solve two mysteries – the identities of both the murderer and the victim – before they reach England and the culprit has the chance to escape.