My Sister Is Going to Kill Me Discussion Questions
The title is a dare. "My Sister Is Going to Kill Me" only works as a thriller hook if the book convinces you, at least for a page or two, that it could be literally true — that Liv or Mandy Chisholm is a real suspect in whatever goes wrong on their Grand Canyon rafting trip, not just a sister being dramatic about a shared vacation. That's the conversation worth having before your club gets distracted arguing about who the actual killer is: does Nina Simon's new thriller earn "sister" as the scariest word in the title, or is the isolated canyon setting — the strangers, the rapids, the days without cell service — doing the work that the sibling relationship was supposed to do?
Some anchor facts before you dig in. My Sister Is Going to Kill Me is Nina Simon's second novel, published by William Morrow on August 18, 2026, at 352 pages. It follows her 2023 debut, Mother-Daughter Murder Night, a New York Times bestseller and Reese's Book Club pick that spent three generations of women solving a murder in Monterey Bay. Simon's path to fiction is its own discussion-worthy fact: before she published a novel, she worked as a NASA engineer, a slam poet, a game designer, and a museum director, and wrote two nonfiction books on community-building in cultural institutions. She's said the new book was inspired by a real whitewater rafting trip she took with her own sister through the Grand Canyon — which means the sister dynamic on the page has at least one foot in something she actually lived.
Quick answer: Liv and Mandy Chisholm — one a color-coded-itinerary planner, one a self-described "bedazzled human tumbleweed" — take their yearly sister trip rafting the Grand Canyon with a group of strangers. When a fellow traveler is found dead and a second body turns up in the water, the trip becomes a murder investigation with no way off the river. The best book club discussion isn't guessing the killer — it's deciding whether the sisters' opposite temperaments generate real tension on their own, or whether the canyon's isolation is propping up a sibling conflict that needed more to say for itself.
The Title's Threat: Sister or Setting?
Start here, because it's the thesis the whole book is either going to earn or dodge. A thriller called My Sister Is Going to Kill Me promises that family is the danger. But the actual jeopardy in the setup — a multi-day rafting trip with strangers, no signal, rapids, and now two bodies — comes almost entirely from the environment and the other passengers, not from Liv or Mandy directly threatening each other.
- Before you finished the book, what did you assume the title meant — that a sister was the literal threat, or that "kill me" was hyperbole about an annoying family trip? Did the opening chapters support or undercut that assumption?
- Which generates more dread in the setup: the idea that Liv and Mandy might turn on each other, or the idea that a stranger in their rafting group is a killer? Which one is Simon actually building toward?
- If you swapped the Grand Canyon for a low-stakes setting — a road trip, a shared apartment — would the sisters' dynamic still be enough to carry a thriller premise? Why or why not?
Liv and Mandy: Opposite by Design
Simon built the sisters as a matched set of contrasts on purpose: Liv is the practical one with the color-coded itinerary, Mandy is the art teacher who brings the spontaneity. It's a familiar sibling archetype — the planner and the wildcard — and the question for your club is whether it deepens into something specific to these two women or stays a type.
- Liv and Mandy's "yearly sister trip" is described as an attempt to bond as their lives increasingly diverge. What does that phrase suggest about where these two stood before the murders — was the relationship already strained, or just drifting?
- Planner-versus-wildcard is a common sibling pairing in fiction. Did the specific details Simon gives each sister (their jobs, their habits, how they pack) make the archetype feel earned, or did it read as shorthand?
- Under pressure, do Liv and Mandy's roles reverse, blur, or hold steady? What does that tell you about which sister the book actually trusts to lead?
Strangers on the River
The rafting group isn't just scenery — it's the suspect pool. A cast of strangers trapped together on a multi-day trip, with no way to leave and no outside help to call, is a classic closed-circle setup, the same engine that powers a lot of the genre's best "everyone's a suspect" plotting.
- What does the closed-circle structure — a group that can't leave the river, can't call for help, and can't verify anyone's story — add that a murder investigation with normal access to phones and police wouldn't have?
- Among the other rafters, who did you suspect first, and was it because of something they said or just because Simon made them seem suspicious on principle?
- Does spending the book confined to a small group of strangers make you trust Liv and Mandy's account of each other more, or does the isolation make everyone — sisters included — equally unreliable?
From Mother-Daughter to Sister-Sister
Simon's debut, Mother-Daughter Murder Night, ran three generations of women through a fixed Monterey Bay setting. This one narrows the family cast to two sisters and moves the danger onto a river with no exit. It's worth asking whether that's an evolution of a working formula or a retreat to safer, more marketable territory.
- What carries over from the mother-daughter-grandmother dynamic in Simon's first book into the sister dynamic here — the humor, the reluctant-partners structure, the sense that family friction is itself a clue?
- Simon has said this book was inspired by a real rafting trip with her own sister. Does knowing that change how you read the sisters' bickering — does it feel more observed and less invented?
- If you'd never read Mother-Daughter Murder Night, would you have guessed this was the same author? What's distinct about how Simon writes sisters versus how she wrote a mother and daughter?
Judging a Book on Release Day
This is a genuinely fresh release — My Sister Is Going to Kill Me published the same week most clubs will be discussing it, so there isn't yet a settled critical consensus or a wave of reader reviews to compare notes against. That's not a reason to skip discussion questions; it's a reason to ask your club to be honest about first-read reactions before they calcify into "what everyone says" about the book. If your group likes pairing a fresh thriller with something more established, see our best thrillers for book clubs in 2026 for comparison points, or browse book club picks about siblings if the sister dynamic is what hooked your group.
- Going in without reviews or a critical consensus to lean on, did you find yourself more generous with the book's pacing and choices, or more skeptical, since you had no external signal telling you what to expect?
- Where do you think the marketing pitch — "whitewater whodunnit" — sets expectations the actual reading experience does or doesn't meet?
- If someone in your club hasn't finished the book yet, what's the one open question from the setup they should be watching for as they read: is it about the killer's identity, or about whether Liv and Mandy actually needed a murder to force them to be honest with each other?
If your club wants sharper prompts than the standard "what did you think" round, our guide to discussion questions that spark real debate has more on picking fights worth having, instead of just going down a list.
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