I Know What You Did Last Summer Season 1, Episode 1 recap: Who died last summer?

Welcome to Wai Huna. This modernized take on Lois Duncan’s 1973 novel occurs in a fictional Hawaiian town where a group of teenagers commits an unforgivable crime the night of their graduation party.  But Amazon Prime’s teen horror series I Know What You Did Last Summer begins in the present, introducing us to one of Madison Iseman‘s two characters, Lennon Grant.

Lennon has just returned home for the first time in over a year after going to college at the University of Michigan. She’s practiced in the art of deception, covering up the scent of menthol cigarettes with spritzes of body spray before greeting her dad, Bruce (Bill Heck). Nothing about Lennon’s return to Wai Huna appears happy to be home. Within minutes of returning, she almost hits a dog in the middle of the road after receiving a cryptic text message with a clown emoji and “I C U.”

If you know the I Know What You Did Last Summer story, you know that driving is always something to fear. Inside her old bedroom, Lennon opens her closet door and finds that someone has scrawled the words “I know what you did last summer” on her mirror in lipstick. They also leave behind something bloody, but we don’t find out what just yet.

I Know What You Did Last Summer Season 1, Episode 1 recap: Who died last summer?

Instead, we flashback to the summer in question, specifically a party with major Euphoria vibes.  Here we get to meet Iseman’s other character, Lennon’s twin sister Allison. Allison and Lennon could not be more different. Lennon is the life of the party, a valedictorian who likes sleeping around and doing drugs like ketamine. She kisses all of her friends on the mouth and appears to do whatever she wants whenever she wants.

In contrast, Allison is quiet and subdued. A wallflower who Lennon repeatedly tries to pressure into doing things she doesn’t want to. Throughout the party, Lennon coaxes Allison into dressing sexier (like herself) and attempts to get her to have sex with Dylan (Ezekiel Goodman), the guy Allison has had a crush on her whole life.

It’s the blowjob lessons that push Allison to her breaking point. She snaps at Lennon and claims she “f**ks” to get everything, including an A in A.P. Bio. Then Allison calls Lennon the “worst person she’s ever met.”

After that explosion, Lennon sets her sights on Dylan, sharing her ketamine with him and seducing him in her best friend Margot’s bedroom. Margot (Brianne Tju) is pissed when she inadvertently walks in on them together, but you immediately get the sense that Margot and Lennon are always fighting and making up.

It doesn’t take long for Allison to figure out what Lennon has done, and their earlier fight pales compared to this one. Allison feels like Lennon takes everything from her, including Dylan.

While the sisters are fighting, the rest of their friends notice the police chief has arrived. The whole party has weird vibes, with all of the teen’s parents hanging out and happy to go along with their kid’s underage drinking. But Riley (Ashley Moore), the resident drug dealer, is especially spooked by the presence of a cop sneaking around. She corrals her friends, including Margot, Dylan, Lennon, and Margot’s gay best friend Johnny (Sebastian Amoruso) into Lennon’s jeep so they can leave before the officer starts sniffing around.

Everyone in Lennon’s jeep is completely f**ked up on drugs and alcohol. They continue to drink while driving, with Margot even recording a video of their antics. Unsurprisingly, Lennon soon hits something on the drive. If you’re familiar at all with the franchise (or, let’s be honest, horror in general), you know they did not just hit a goat. It’s Allison’s body they find in the road.

Before they can figure out how to handle this traumatic incident, their classmate Dale pulls up, which I assume might become relevant later. Riley and Margot placate Dale by claiming they’re hanging out on the side of the road because Margot wasn’t feeling well, which she backs up by retching all over the side of Dale’s car. Satisfied with their explanation, he drives off.

The next step is for the group to figure out what they’re going to do about Allison’s body. Dylan and Johnny want to do the right thing and call the police, but Riley and Margot argue that they are all 18, and if they do that, their lives are over. Not to mention that Lennon was driving, which means she’d get the harshest sentence of all, and there is illegal stuff all over the car. Needless to say, they can say goodbye to college and potentially go to jail for manslaughter.

It takes some arguing, but they eventually agree to take Allison’s body to a nearby cave where Allison and Lennon’s mother previously committed suicide. It’s sort of poetic, in an extremely morbid way. Also, apparently, a bunch of cult members killed themselves in the cave. Their names are carved into the stone. No one knows who did the carving.

I Know What You Did Last Summer Season 1, Episode 1 recap: Allison is not the dead twin, after all

With Allison’s body left in the cave, we get a flashback-within-a-flashback to Allison and Lennon’s fight earlier that night. Lennon told Allison that their mother didn’t love her, and Allison ripped off her necklace and gave it to her sister. It’s revealed that the person who died was not Allison but Lennon. That means that Allison has been impersonating Lennon all along.

Not only that, but someone saw the group go into the caves and leave again. When they arrived, they startled a woman who might have been trying to kill herself. She hid out of sight until they left. I’m guessing we’ll see her again in the coming episodes.

To clarify, when we saw “Lennon” in the present day, it was actually Allison pretending to be Lennon, so moving forward, I’ll just call her Allison. Before the episode wraps, we return to the present-day to see what Allison found in her closet. A giant bleeding goat head. If only it had been a goat!

The first three episodes of I Know What You Did Last Summer are now streaming on Amazon Prime Video. The fifth episode will start streaming Friday, Oct. 22.