Mariah Mundi (Aneurin Barnard) and his younger brother Felix (Xavier Atkins) don't take their parents' (Ioan Gruffudd and Keeley Hawes) jobs seriously. The adults are professors at a university in England, but secretly work for an organization tasked with protecting ancient artifacts. One of these artifacts is the Midas Box, a box thought to turn everything placed inside to gold. Of course, the box is supposed to by a myth, but Otto Luger (Sam Neill) is searching for the box, myth or not, and is close to finding it.
When Mariah's parents vanish and Felix is kidnapped, Mariah is sent to a remote island hotel by Charity (Michael Sheen) to spy on Otto. He gets help from Sacha (Mella Carron), a maid in the hotel, and they set off on their own adventure to find the Midas Box before Otto and his accomplice Monica (Lena Heady) and protect it from misuse. The Adventurer: The Curse of the Midas Box sets out to be a grand adventure that families can enjoy, but is bogged down by a ridiculous plot, cringe-worthy dialogue, and wooden characters. The film boasts a lot of fantastical happenings that try to make sense of themselves, but fall short of making the plot any better. It is instead a tangled web that the writers have written themselves into with no plausible way out.
The cast includes big names, most of which are over-the-top and badly written characters, and others, like Ioan Gruffud, are in the film for about three minutes. Blink and you'll miss him. Michael Sheen's character is meant to be the funny mentor, but his role isn't quite clear in the larger scheme of things. For example, he also comes to the hotel after Mariah does, only in a magician's disguise. But if he's also there to investigate, then why not tell Mariah what his plan is, instead of leaving the teenager to his own devices and hoping he'll figure everything out? That sounds irresponsible and unnecessarily complicated.
Also, Aneurin Barnard has no charm, charisma, or any real will as Mariah. And as the lead character, he comes off as too flat and not someone we can get behind. A lot of the time, his expression remains severe, and his trust of Sacha proves unreasonable, seeing as how she does nothing to prove she is trustworthy. Instead, her inclusion into the story stems from the need to have a female protagonist somewhere in the movie, which doesn't add anything to the film except for the audience's confusion. The dialogue and the need to include several side adventures and information are the major drawbacks to the film outside of the characters. The film, which is based on the novel by G.P. Taylor, includes so much eye-rolling dialogue that it's hard to take the film seriously, even though it takes itself seriously. There's just too much going on sometimes, most especially in the finale, as though it's singularly trying to cram in everything at once and it can be headache-inducing.
Unlike the title suggests, the film isn't really all that adventurous. There's no thrill to the tale that unfolds, and it frustrates far more than it excites. Uninteresting characters, questionable plot, and bad dialogue make this film rather stale and the complete opposite of what the expectation is. Forgettable and flat, the film tries and fails at being an adventure that the entire family can enjoy.
