What actually happens
A resort that hands out drinks and maps to the nice beach
Guy and Prisca Cappa's marriage is ending, so they bring Maddox and Trent, their young kids, to a tropical resort for one last family trip. An employee named Madrid gives the parents free drinks, and the kids make friends with Idlib, the nephew of the resort manager, Nils. That night the children hear their parents argue and play a code game Idlib gave them. The argument also reveals that Prisca has an ovarian tumor, which is benign and slow-growing. The next day Nils sends the family off to a secluded beach. Brendan, a rapper who goes by Mid-Sized Sedan, is already there with a woman who is with him. They are joined by Charles, a surgeon, who brings his mother Agnes (elderly), Chrystal (his wife) and Kara (their daughter), and by a married couple, Jarin and Patricia Carmichael.
Reading this instead of watching it is the correct decision. Scaredy Cat makes that decision automatic, for free.
One birthday every half hour, no cake
Trent finds the body of the woman who came with Brendan. Charles gets suspicious of Brendan, who explains that his nosebleeds come from hemophilia. Then the children turn into teenagers within minutes and Agnes suddenly dies, and the families work out that the beach is aging them at a year per thirty minutes. Each family has at least one member with a medical condition, and anyone who tries to leave blacks out and wakes up back on the beach. Charles cuts Brendan with a pocketknife in anger, and the wound heals almost at once. Prisca's tumor grows fast enough to threaten her life, and Charles removes it with surgery. Brendan's companion has fully decomposed in a few hours. Kara and Trent, now in their late teens, get together, and Kara's pregnancy runs on the beach's clock. She gives birth, and the baby starves as time rushes past.
Everyone's chronic condition files a complaint
Charles's schizophrenia gets worse, and he kills Brendan. As the day goes on, Jarin drowns on a swim to find help, Kara falls to her death while climbing the mountain, and Patricia has a fatal epileptic seizure. Guy's eyesight starts to blur and Prisca begins to lose her hearing. Trent and Maddox find a notebook left by an earlier visitor. It is full of names, all of people who died on the beach, and it hints that someone has been watching them. At night Charles has a schizophrenic episode and attacks Guy and Prisca. Prisca runs, and Charles keeps attacking Guy.
Chrystal and the scene with the bones
The scene people dread most is Chrystal's. Her hypocalcemia makes her bones rupture and heal wrongly, over and over, until her body is gruesomely contorted and she dies. It happens late in the story, after the group has already begun to fall apart. In the same stretch, Prisca comes back and slashes Charles with a rusted knife, which gives him a fatal blood infection. Guy and Prisca, now elderly, make peace with each other and die of natural causes a moment apart.
The ending, explained
By the next morning only Maddox and Trent are left, both middle-aged. They build a sandcastle, then go back to the secret message Idlib gave them. Trent decides it points to an underwater coral passage and that swimming through it might get them off the beach without blacking out. Maddox's swimsuit snags on the coral, and a resort employee watching them reports that the whole group is dead. His contact, Sidney, hints that a guest once nearly escaped, and Nils announces that trial 73 is finished. The resort is a front for researchers from the pharmaceutical company Warren & Warren, who spike the drinks of guests with medical conditions to test new drugs, and the beach lets them finish a lifetime of testing in one day. Trent and Maddox survived the swim. They interrupt Nils and Madrid as they prepare the next group and give the notebook to a vacationing police officer, Greg Mitchel. Everyone named in it is a missing person, so he reports the researchers, who are arrested. He plans to return the pair to their aunt.
The post-credits ruling
There is no post-credits scene. You can leave when the credits start.
✓ Spoiled safelyDog status: not fine, but it is only mentioned.
Questions people ask at 1am
Is Old scary?
Old is a 5 out of 10 on the scare scale, with dread that lasts about a night. The fear comes from watching people age and fail in a few hours, and from a few scenes of body horror.
How does Old end?
Almost everyone on the beach dies of age, illness or injury. Trent and Maddox swim through an underwater coral passage and survive, and their notebook of missing people gets the resort's researchers arrested.
Does the dog die in Old?
Yes, the dog dies in Old, but only as a mention. A character says it died of old age, and the movie never shows the death or a body.
Is there a post-credits scene in Old?
No. Old has no post-credits scene, so you can leave when the credits start.
Why are the people on the beach aging so fast in Old?
The beach speeds up life to about a year every thirty minutes. The resort uses that to run lifelong drug trials on guests with medical conditions in a single day, after spiking their drinks.
