Old Ending Explained (Spoilers)

A vacationing family discovers that the secluded beach where they're relaxing for a few hours is somehow causing them to age rapidly, reducing their entire lives into a single day.

Old: Spoilers Below

The Kapa family – Guy and Prisca, and their kids Maddox and Trent – arrive at a posh resort for a family vacation. Trent quickly becomes friends with a young boy named Idlib, and they spend their time playing games like decoding messages using a special code that Idlib taught Trent. Guy and Prisca discuss that they wanted to give the kids one last trip before they divorced. This is made worse because Prisca has a tumor.

At breakfast, a doctor named Charles is eating with his young, vain wife Chrystal, daughter Kara, and mother Agnes. Nearby, a woman named Patricia is experiencing an epileptic seizure, which Charles treats while Patricia's husband Jarin also tries to help. Trent sees Idlib at the resort, but the manager makes him leave.

The Kapas family, plus Charles and his family, board a van to go to a private beach. On the beach, Maddox recognizes Brendan, a rapper whose stage name is Mid-Size Sedan. Earlier, Brendan was seen with a female companion who went skinny-dipping. The youngsters frolic with each other while the grown-ups rest on the beach. Deserted dolls left behind by other kids are found by the girls. Trent stumbles upon the corpse of Brendan's friend while swimming near a cave. The adults investigate the body, which seems to have drowned, while Brendan deals with nosebleeds and is dumbfounded by the discovery. Charles believes Brendan is up to something nefarious, even though Brendan says the woman only went for a swim and didn't come back. Soon after, Agnes starts having trouble breathing before she too dies.

Jarin and Patricia also arrive at the beach, but the people who brought them have already left. The kids also begin to experience something strange. Brendan tells the adults that his constant nosebleeds are due to his hemophilia, and that the woman he was with has multiple sclerosis. Patricia and Jarin talk to Maddox and Trent, who have both aged significantly, along with Kara.

Several people try to leave the beach by going through the rocks that separate it from the rest of the world, but they all pass out and wake up back at the beach before they can make it through. They also notice strange things happening, like when Charles stabs Brendan with a knife, the wound heals almost immediately. A short time later, Brendan realizes that the woman he was with has decomposed into nothing but bones within hours. He realizes that something is happening that is related to time. The sudden pain in Prisca's stomach is caused by a tumor. The adults try to help her, feel around for the tumor at first, describing it as small as a golf ball. The grown tumor is removed by surgery, which is comparable to the size of a cantaloupe. The cut in Prisca’s stomach rapidly heals after the surgery.

As Trent and Kara age even further, they have sex and Kara becomes five months pregnant within minutes. The adults prepare for the birth, which happens rapidly, but the infant dies after a minute due to lack of care. As the other adults start to show more visible signs of aging, Chrystal finds the process much harder to deal with than everyone else.

Charles begins to experience delusions and psychotic symptoms associated with schizophrenia, eventually leading him to stab Brendan to death. The others take his weapon away while trying to come up with an alternate plan of escape. As Jarin tries to swim to find an escape, Trent and Maddox come across a notebook with names and medical conditions of previous visitors. They also see people in the distance watching them.

Maddox and Prisca discuss the status of her relationship with Guy. Prisca confesses that she has been seeing someone else. Maddox goes to the beach to try and find a way out herself after she grows angry with Prisca. While there, she finds Jarin's body which seems to have gone unconscious before drowning. Patricia suffers a fatal epileptic seizure after seeing Jarin's corpse. Desperate to find a way out, Kara starts climbing up the rocks but blacks out and falls to her death before she can reach the top, leaving Trent devastated.

It's nighttime, and Charles is getting crazier by the minute. Chrystal is losing her mind over her rapidly aging body and declining physical health, while Guy is losing his sight. Prisca is also noticeably grayer than before. Guy and Prisca discuss the other man in Prisca's life, with Guy admitting he was aware of him and wishing he could have done more to keep their marriage intact, but also acknowledging that the other guy is a loser and that she deserves someone better. Charles then begins to attack Guy and Prisca, while Trent and Maddox are attacked by Chrystal when they attempt to look at her. She enters the cave after them and meets a gruesome death, her body contorted at horrible angles. Prisca then slashes Charles with a rusty knife, causing an infection that kills him rapidly.

The Kapas then congregate around the campfire and the beach. Guy is having a difficult time speaking and recalling things, but he essentially admits to Prisca that he still loves her just before he dies. Prisca then stands up for a moment but collapses and passes away by Guy’s side while both kids grieve their parents.

Trent and Maddox, now in their 50s, discuss a code that Trent had received from Idlib. Trent realized that the code means “My uncle doesn’t like the coral”. The siblings then realize that the reef must be their way out. They swim out to the coral, but Maddox's clothing gets snagged. They don't come back up, so the van driver reports to his bosses that everyone in "Trial 73" has died.

The beach resort is actually a front for a medical research team that uses people with medical conditions for clinical trials of new drugs which they administer to the guests through cocktails. They know that the beach speeds up the aging process, so they reduce the trials to a whole day for more effective results. The researchers believe they were successful in curing Patricia’s epilepsy since she didn’t have a seizure for eight hours - the equivalent of 16 years on the beach.

The resort manager tries to lure in more victims until Trent and Maddox intervene after escaping from the coral. Trent finds a man who he knew as a police officer from when he was younger. Trent gives the officer the notebook, which reveals the truth about all the missing people. Idlib comes out and recognizes Trent as an adult. The resort staff realizes they are in trouble after Trent and Maddox tell the officers what happened to them.

The resort employees are arrested by the authorities, while Trent and Maddox are taken to their aunt's house. She is not ready to see that her niece and nephew are full-grown adults.

Old Ending Explained (Spoilers) - ALL HORROR Tweet it