
Old is a 2021 American horror thriller film written, directed, and produced by M. Night Shyamalan. It is based on the French-language Swiss graphic novel Sandcastle by Pierre Oscar Levy and Frederik Peeters. As with most M. Night Shyamalan films, there is a significant plot twist in the story denouement, which ultimately will affect the viewers’ enjoyment of the film, depending on whether one is able to accept the logic behind said plot twist.
S P O I L E R S
The premise of Old sounds like something ripped out of an original Twilight Zone episode viz.
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. (IMDB)

The above-mentioned family consists of married couple Guy and Prisca Cappa (Gael García Bernal, Vicky Krieps respectively) with their young children Maddox and Trent (eleven and six years). There are also two other couples as well as another family on the beach at the same time as the Cappas.
The first act introduces us to the beach resort the Cappas are visiting and the main thrust of the story is inserted when Trent discovers a corpse in the sea and the rest of the characters realise that they are inexplicably aging one year every thirty minutes and unable to leave the beach, blacking out whenever attempting to do so.

The entire second act depicts the consequences of this premise on the characters and how they deal with this shocking discovery. Considering the stress being put on the characters, not much work is needed to develop the characters beyond showing how each character responds to this dire situation.
Obviously, much of the second act also involves the characters in various attempts to escape the beach and its deadly effects and failing to do so each time. Inevitably, the third act finds the final survivors – Maddox and Trent – now in their fifties making a last ditch effort to escape (the manner of which is rather unsatisfactory – a decoded letter from one of Trent’s friends tips them off to a possible solution), which they do.

Then comes the twist – the resort is a front for a research team conducting clinical trials of new medical drugs, who have been using guests with medical conditions as unwitting test subjects. Since the beach naturally accelerates the lives of the guests, the researchers have been able to complete the drugs’ lifetime trials within a day.
However, considering the fact that typically, nobody survives the aging effects of the beach or is able to get off the beach successfully, how was the beach originally discovered to begin with? That is unexplained, plainly because it makes no sense whatsoever. That needs to have happened in order for this entire charade to exist in the first place.
Perhaps Old would have been more effective without the need to feature a plot twist – like in the original source material. The focus then would have been on life and death and the perception of time, without having to tack on some explanation for the phenomenon at the end. Certainly would have been more poignant and thought-provoking than what Shyamalan settled on. Avoid.
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