In an unknown time, a little boy is seen from behind, running through the woods. The boy stops at the water’s edge, ahead of the pond. An elderly woman stands beside him. She tells him the pond will always take him where he needs to go.
In the present day, Kat, alongside Alice, tells Del that she knows what happened to Jacob. Del tells Kat to let it go. Kat runs out to the pond with Alice chasing behind her. She dives in but the pond rejects her. Alice pleads with her to stop trying. When Alice dives in after her mom, she gets trapped under the part of the pond that’s frozen over with ice. Kat comes back up, swirling around the icy water in search of Alice. She finds her and brings a limp Alice to shore while screaming for help. After performing mouth-to-mouth, Kat resuscitates her.
The next morning, Kat arrives at Elliot’s front porch only to find a goodbye note addressed to her on the door.
Kat and a recovering Alice sit at the edge of the pond with ideas about what happened to Jacob. Alice suggests they go find him after the pond melts and Kat refuses, declaring they must be done with the pond.
Some time passes. Kat goes for a summer run, and as she passes Elliot’s house, she takes a moment to stare. Meanwhile, Del tends to her fields. When an unknown horse appears and stands behind her, they lock eyes before the horse bolts. Back home, Spencer arrives to give Alice a ride to school.
Kat and Monica are in downtown Port Haven. Kat shares that Alice is going away to be with Brady for the summer. Kat is now the editor-in-chief at The Herald, and she receives a call about a death in town.
At the Landrys’, Kat, Del, and Rita are discussing the bad news. Evelyn Goodwin, the oldest member of the town’s wealthiest family, has died. Alice walks in and delivers mail from Elliot, who has been sending postcards from around the world. Alice rolls her eyes as Kat is visibly hurt.
Over dinner, Alice learns Evelyn’s family founded Port Haven and Lingermore was the name of their palace. Kat reminds Del that their lineage (Rebecca and Elijah Landry) were founders, too. They rise from the table and dance to Len’s “Steal My Sunshine.”
In Jacob’s bedroom, Kat sits with documents and notes. Alice enters and Kat shares she hasn’t made much progress with her research on Jacob. Alice thinks it’s easier to solve the mystery through the pond, but Kat reminds her that Elliot disagreed. After Alice leaves, Kat receives a call from Brady. Kat shares that Alice is the glue in her bond with Del. They hang up and Kat receives another call.
At the Point Café, Kat informs Monica that Evelyn put The Herald in her will. Additionally, there are historical artifacts she left behind, and she will have to go to Lingermore to get them. Just as they discuss the trip, Del enters and shares that she’s going too.
They arrive and are greeted by the lawyer who is overseeing the dissolution of Ms. Goodwin’s estate. The lawyer informs Kat that Evelyn died before she could open a museum of her family’s artifacts. Now that’s she’s gone, it’s all Kat’s. Kat goes through the boxes. She stares out the window and is overtaken by old memories.
Before leaving, Alice goes to the pond to say goodbye. She leans over and lets her fingers touch the water. She discovers a bracelet in there. It’s the one she threw in when she first arrived at Port Haven.
Back at Lingermore, Del steps into another room of the palace and calls out to Evelyn in a familiar way. In another room, Kat observes a painting of a 19th century woman that resembles her. The photo inscription reads “My Katherine 1814.” Kat is stunned and takes a picture of it.
Back at home, Alice is packing to leave. Kat and Alice are both brimming with secrets to share.
The next morning, Kat jogs by Elliot’s and finds him at home. Kat invites Elliot to Del’s goodbye party for Alice. Although Alice is surprised that Kat invited Elliot, Del is happy she did.
At the party, Kat notices that Alice is wearing her lost bracelet. Alice lets out a nervous laugh before Elliot walks up with champagne in hand. Alice’s face falls. Kat walks into the house and Elliot follows her in. Kat tells Elliot Alice felt abandoned by him.
Alice is in the living room when Del approaches. She informs Alice of Elijah and Rebecca Landry’s initials on the fireplace. Alice confesses she doesn’t want to leave Port Haven for the summer. Del tells Alice that the farm will always be there waiting.
That night, Del and the guests are seated around the fireplace. Del holds a box of fireworks that are in honor of Colton. As fireworks go off, Del hopes the group feels Colton there with them. Del slips into a memory of the past.
The fireworks transition back to 1999. Colton and teen Elliot are in conversation. Colton tells Elliot – in regard to Kat – to never waste time because it’s never guaranteed.
In 2024, Alice observes a look between Elliot and Kat. When Alice wants to know if they are together, Kat tells her that they were, and it didn’t last. Alice believes it’s her fault.
At the cove, Alice meets her friends at a bonfire. She thinks of Elliot and has a vision of teen Elliot around the fire. Alice blinks and then he’s gone.
In the clubhouse, Kat plays a mixtape that Elliot once made. When Elliot arrives, Kat tells him she has given up time-traveling. Elliot apologizes for not saying goodbye before leaving, but Kat tells him to just listen to the music. Although they share a kiss, Kat pulls away.
It's 1999 at the cove, and teen Nick encourages teen Elliot to talk to teen Kat as he got Colton’s approval. Kat leaves the bonfire and Elliot says he will tell her later. Back in 2024, Spencer gives his jacket to a cold Alice. It reminds her of her time with teen Nick. The group encourages her to sing a goodbye song with her guitar. She takes off instead.
At home, Del and Kat talk about Lingermore. Del admits that she wants to work on her relationship with Kat.
In Alice’s bedroom, Kat walks in and Alice shares that she misses the past. She confesses she went to the pond, where she found the bracelet. She tells her mom that she threw it in when she first arrived, and the pond recently gave it back. Kat shares her secret too, showing Alice the portrait she saw at Lingermore. Kat says she must time-travel to find out why she’s in a portrait from 200 years ago. Alice believes its connected to Jacob. Alice pleads for one last trip together.
From his home, Elliot observes Alice and Kat heading to the pond. He erases the romantic text he was drafting to Kat.
Outside, Del is cleaning up the fireworks when a farmer, Hank, drives up. He tells her he sold the farm, and the buyer doesn’t want to take over the lease on her fields. Del says she will take care of the farm by herself. As Hank drives off, the ghost horse appears again.
Kat and Alice jump into the pond and Kat is violently yanked into the portal by a seaweed that wrapped around her leg. Alice screams and pushes herself up, resurfacing in a panic. She screams for Kat and doesn’t know if she’s transported or not until teen Elliot appears at the pond’s edge. Kat resurfaces but she is alone without Alice. Kat scrambles onto the rocks and a gun appears and shoots her. She falls into the pond and floats face-down.