[Review] “I Know What You Did Last Summer” Is a Polarizing But Fascinating Slasher Mystery

Note: This review is based on the first four episodes screened for critics.

Lois Duncan’s 1973 suspense novel I Know What You Did Last Summer was loosely adapted into a slasher film in 1997. The adaptation took the core concept, which saw a group of high school seniors commit a fatal hit and run after a night of partying. It transformed it into a teen horror movie wildly different from the source material. “I Know What You Did Last Summer” series showrunner Sarah Goodman takes a similar approach. Outside of its setup, this series has zero interest in retreading familiar ground. Fantastic deaths and a gripping murder mystery pull you in, even when its mostly unlikeable leads tend to polarize.

Madison Iseman stars as Lennon and Alison, twin sisters that couldn’t be further apart in personality. They, along with fellow friends Dylan (Ezekiel Goodman), Margot (Brianne Tju), Riley (Ashley Moore), and Johnny (Sebastian Amoruso), celebrate their high school graduation at a house party full of drugs and lust. Eventually, the teens find themselves grappling with a harrowing choice after a fateful collision that results in a dead body. One year after trying to bury their mistake, the teens find themselves the target of a brutal killer that seems to know their darkest secret. But this small Hawaiian town is full of secrets, as well as suspects. They’ll need to survive long enough to discover the killer’s identity.

The pilot episode, directed by Craig Macneill, sets up the season-long mystery with its inciting event and an introduction to the very messy lives of these teens in small-town Hawaii. All isn’t swell in paradise, long before death comes knocking. These teens are chaotic in extra dramatic ways that paint them intentionally unlikable. They partake in all the vices and then some, and that’s before blackmailing, backstabbing, and egregiously selfish behavior enter the equation. You can count on this friend group to make the worst judgment calls at every turn, a move that feels genuine yet will grate all the same.

Goodman bides her time peeling back the complex lives and secrets of not just the core leads but the surrounding town residents as well. The consistent spider imagery runs a bit too on the nose for the very, very tangled web Goodman is spinning here. The more the series progresses, the murkier things get. It succeeds wholly in ensuring an unpredictable mystery that continues to surprise. When you think you’ve nailed a reveal, the series makes a shocking left turn.

Of the first few episodes, the kills bide their time in arriving. When they do, however, they’re brutal and oh so satisfying. The slasher element works in service to the central mystery, which grows increasingly complicated by the episode. What begins as a small, contained murder mystery expands in a fascinating way that hooks you.

So far, “IKWYDLS” invests more of its effort into the mystery than redeeming any characters for appalling behavior or choices. They may not engender themselves well to the viewer, but the slow trickle truth of who they are and their many secrets makes for a propulsive watch all the same. The season’s attempts at occasional humor, mainly by a puzzling supporting character, land with a thud. The adults in this bizarre little town are just as odd and eyebrow-raising.

At the halfway mark, it’s clear that the town’s dark secrets and lousy behavior extend generations, and the answers are still far out of reach. Wading through the excess drama will likely prove divisive—especially those with a deep attachment to the 1997 adaptation. But the deaths are delightfully gory and grim, and the audacious approach to the material makes for a surprisingly binge-able watch.

Amazon will release the first four episodes of “I Know What You Did Last Summer” on October 15, with new episodes available every Friday.