Something in the Water by Catherine Steadman is an adult psychological thriller published by Ballantine Books in 2018. When Mark and Erin Roberts decide to keep a mysterious duffle bag full of dirty money and gems, they start down a rode of criminal behavior, secrets, and greed. Something in the Water examines the lies we tell and how far we’ll go to protect those lies. The book was a #1 New York Times bestseller and named one of the best books of the year by Glamour and Newsweek in 2018. It was also a finalist for the ITW Thriller Award and has been optioned for film by Reese Witherspoon’s production company, Hello Sunshine. Steadman grew up in New Forest, UK. After training at the Oxford School of Drama, she went into stage and film acting, her most well-known role as Mabel Lane Fox on Downton Abbey. She has also published Mr. Nobody (2020) and The Family Game (2022).

This guide follows the 2018 edition of Something in the Water.

Plot Summary

Something in the Water opens with Erin Roberts desperately digging a grave for her dead husband, Mark Roberts. As she digs, Erin reflects on the chain of events and choices that brought her to this moment. With an appeal to the reader to decide whether she’s a bad person, Erin starts her story at the beginning of when things went wrong, about three months before.

Erin and Mark live a comfortable life. Erin works making documentaries and steadily climbing the creative ladder. Her current project involves interviewing three convicts before and after their prison releases. Mark’s job in banking eats much of his time but pays well enough for Erin to pursue her dreams. When Mark loses his job, his downward spiral of anger and fear begins. He and Erin discuss changing their lifestyle and selling their house. Their one concession to cutting back on their spending is their honeymoon in Bora Bora, which will be their last extravagant experience.

While enjoying the island, Mark and Erin find a duffle bag containing stolen money, an iPhone, and a USB full of incriminating documents. The bag came from a downed plane owned by a practically invisible corporation. They are sure the company won’t pursue them because its operations are illegal, so Erin and Mark decide to keep the bag.

Their decision sparks a series of increasingly poor choices and criminal behaviors. It begins simply enough—eliminating themselves from the hotel computer to cover their tracks and smuggling the bag’s contents home. Mark and Erin find ways to deposit the money and sell the gems, all the while trying to stay one step ahead of the authorities and anyone who might be searching for them.

When a couple (Sally and Daniel Sharpe) who was vacationing in Bora Bora at the same time as Mark and Erin dies under suspicious circumstances, Erin becomes convinced that the original owner of the bag killed the couple by mistake. Her fears mount when strange messages appear on her voicemail and her home is broken into. Desperate to be rid of the bag once and for all, she turns on the iPhone in the bag—even though doing so will reveal her location—to make certain no one’s after her. She finds a recent voicemail Mark has listened to. In addition to the strange events, Mark has been lying to her.

The voicemail is from a man who will pay handsomely for the incriminating documents from the bag. Erin arranges to make the exchange while Mark is away on business. Hiding in the woods waiting to make the trade, Erin sees Mark and another man. Mark finds the USB and tells the other man Erin won’t get in their way. Devastated, Erin realizes Mark betrayed her. The other man shoots Mark, killing him. To cover her own illegal activity, Erin buries Mark’s body and the evidence of her crimes, bringing the narration full circle to Chapter 1.

Following the coverup, Erin reports Mark missing and picks up the pieces of her life. She grows closer to two former convicts (Eddie Bishop and Alexa Fuller) who were part of her latest documentary and prepares for the future. Mark’s lies weigh heavily on her. Erin is pregnant with his child, and she wonders if he ever truly loved her, a question she will never get answered.