This is a semi-entertaining, reasonably decent family animation that begins promisingly with a swell of adventure as a young boy sets sail in a boat in search of his missing dad. But after a couple of hastily resolved peril-at-sea moments (“We’re done for! We’re saved!”) the script lurches into a bizarrely un-childfriendly storyline about a secretive cult.

The boy is 12-year-old Felix (nicely voiced by Daniel Brochu), who lives in Quebec’s Magdalen Islands with his mum and little sister. Two years earlier, his fisherman dad was lost at sea. Any hope that he might be alive is long gone, but Felix is determined to search the island where he was last spotted. He ropes in grumpy lighthouse-keeper Tom to help – a real old Captain Birdseye with a bushy beard and eyebrows like furry white caterpillars.

There are some gracefully animated scenes as the pair sail off, all glowing sunsets and churning waves. But when they get shipwrecked, it all goes headspinningly wrong. They discover that an evil cult has built an underground city on the island where Felix’s dad went missing. The group’s leader Morgäa (Karine Vanasse), a woman with flicky, over-the-top Real Housewives hair and bling sunglasses, rejects the label “cult”. “The residents come here entirely of their own accord,” she trills. “They’ve adopted a peaceful, sincere lifestyle based on principles of harmony.” This satire of lifestyle gurus here is pretty low on gags, and it’s hard to see how it will connect with younger viewers.

The rest of the movie plays out in standard kids’ entertainment frantic mode, the group’s security beefcakes chasing Felix and Tom around, everyone bopping each other on the head. Spoiler alert: Morgäa’s power is linked to immortality; adults get turned into babies, kids are threatened with premature ageing. It’s a neat idea, but the script doesn’t take it anywhere interesting.

• Felix and the Hidden Treasure is released on 4 June in cinemas.