The novel centers around a newlywed couple, Erin and Mark, who stumble upon a mysterious object while scuba diving. This discovery, shrouded in secrecy, becomes a turning point in their lives. They are forced to grapple with the weight of their knowledge, constantly looking over their shoulders and questioning their choices. The story explores the corrosive effect of secrets on relationships, highlighting how the desire to protect oneself can ultimately lead to destruction.

Steadman masterfully contrasts the idyllic setting of Bora Bora with the unraveling lives of Erin and Mark. Their honeymoon, initially a picture of love and blissful escape, quickly morphs into a battleground of fear and paranoia. The pristine beaches and turquoise waters serve as a stark counterpoint to the darkness that festers beneath the surface, both literally with the "something in the water" and metaphorically with the couple's hidden truth.

The novel grapples with the complexities of ethical dilemmas. Erin and Mark are forced to make impossible choices, constantly weighing the potential consequences of their actions. As they descend deeper into their web of deceit, the line between right and wrong becomes increasingly blurred. "Something in the Water" compels us to question our own moral compass and consider how far we would go to protect ourselves and those we love.