My Sister Is Going to Kill Me: A Book Club Pick

Nina Simon's setup is Liv and Mandy Chisholm's annual sister trip, a ritual the two of them keep up as their lives pull further apart. Liv is the buttoned-up government agent who shows up with color-coded itineraries. Mandy is the free-spirited art teacher, described as a kind of bedazzled human tumbleweed. This year the trip is a rafting run through the Grand Canyon, organized by Babette, the head of a wellness empire — who books the sisters onto a raft full of strangers and then doesn't show up herself. When a fellow traveler turns up dead, then a second body hits the water, the vacation becomes a murder investigation with the sisters both inside it and suspicious of each other.

That's the mechanism worth noticing before your club even opens the book. Most thrillers spread suspicion across a full cast — eight strangers on a boat, any of whom could plausibly be guilty, which makes for fun but scattershot theorizing. Simon collapses that field to two people who've known each other their entire lives, which means every reader arrives with a built-in framework for judging them. You don't need the book to establish who Liv and Mandy are before you can have an opinion about which one is capable of what. You already know sisters like this. You might be one.

A closed circle with no exit

The Grand Canyon setting isn't just scenery — it's the plot device doing the actual work. A rafting trip at the bottom of a canyon means no cell service, no road out, and a fixed, shrinking cast of suspects trapped on the water together for days at a stretch. That's the classic closed-circle mystery structure, the same engine that makes isolated-setting thrillers so discussable in the first place: everyone present had opportunity, nobody can simply leave, and the group has to keep functioning — paddling, camping, eating meals together — while suspicion curdles underneath. If your club has worked its way through the wave of cabin-in-the-woods and cruise-ship thrillers over the past few years, you already know why this setup reliably produces good meetings; see our roundup of the best thrillers for book clubs in 2026 for more of that isolated-setting DNA. What Simon adds is that the two people with the most opportunity, and the most motive-adjacent history, are family — which raises the discussion stakes past "who had access" into "who do you actually believe."

The real argument is about the sisters, not the corpse

Reviewers keeping tabs on advance copies describe Liv and Mandy in the classic sibling register: fierce loyalty shading straight into the specific, private urge to strangle the person you'd also die for. That's the discussion your club is actually going to have, and it's richer than a standard whodunit debrief. Ask your group who they sided with on page one, based on nothing but the setup, and you'll get answers rooted in their own family — the responsible older sibling who resents being the responsible one, the wildcard younger sibling who's tired of being underestimated. Then ask again after the twist lands. Watching people's loyalties move, or refuse to move, tells you more about your club than most reveal-driven thrillers ever manage. It's the same instinct that makes family-inflected mysteries perennial book club favorites — worth pairing this one against a few other titles that lean on relationship tension as hard as they lean on plot; our guide to the best mystery books for book club discussion has several that reward the same kind of side-taking.

Simon has already proven this works

This isn't Nina Simon's first attempt at turning a family bond into a crime-fiction engine. Her debut, Mother-Daughter Murder Night, was a New York Times bestseller, a Reese's Book Club pick, and an Anthony Award winner — built around a grandmother, mother, and daughter forced into amateur sleuthing together, with the family friction doing as much narrative heavy lifting as the murder itself. My Sister Is Going to Kill Me takes the same instinct and sharpens it: two people instead of three, a title that states the accusation outright, and a setting that won't let anyone walk away from the argument. If your club liked what Mother-Daughter Murder Night did with generational tension, the sister dynamic here is tighter and more combustible — less room for a peacemaking third party, more pressure on exactly two relationships.

Pick this one for a club that's tired of the post-reveal silence. The title guarantees you'll have opinions walking in, the canyon setting guarantees nobody can dodge the conversation, and the sister relationship guarantees the argument survives the last page — because "which sister do you believe" was never really a plot question. It's a people question, and those don't resolve just because the book ends.