There’s a popular meme, spread across various social media platforms, where users upload a photo or video of themselves engaging in a series of increasingly ridiculous poses or actions. It’s accompanied by variations of the phrase “Never let them know your next move” – a cheeky imperative warning against predictability. Unlike participants in this trend, the team behind Aquaman and the Lost Kingdom isn’t afraid of doing what’s expected. They seem to prefer it.

James Wan’s sequel to his 2018 blockbuster Aquaman is frustratingly committed to formula. There are few surprises in this story of how Jason Momoa’s Arthur balances the responsibility of ruling his underwater kingdom with the challenges of parenthood. There are even fewer inspired moments in the screenplay, which moves between clunky exposition laying out more Atlantis lore and a string of punchlines in search of a joke. Somewhere in there, screenwriter David Leslie Johnson-McGoldrick shapes a story about family men and geopolitics that you’ve seen done better and with more vigor elsewhere.

Arthur remains hot and chiseled, but his life is different. The film opens with a reintroduction to the aquatic superhero, narrated in voiceover by Momoa. After defeating his brother Orm (Patrick Wilson), Arthur married Mera (Amber Heard) and had a son. He splits his time between his childhood home above ground and the underwater metropolis Atlantis.

When Arthur isn’t sleep-training his cherubic heir, he’s dozing off during council meetings or mediating in his constituents’ beefs. Through policy meetings and diaper changes, Momoa approaches his character with the same charming and goofy wit. Arthur might have the integrity worthy of the crown, but he’d much rather revel in the joys of fatherhood than keep the throne warm.

Alas, duty calls. Aquaman’s nemesis, Black Manta (more Yahya Abdul-Mateen II, please!), still needs to avenge his father. In the last film, Aquaman destroyed the leather-clad villain’s suit with his mighty gold trident. So before Black Manta (who’s just David Kane when not wearing the insectile mask) can engage in another battle, he needs to fix his gear.

An expedition led by Dr. Shin (Randall Park) to find Atlantis-level technology to charge the suit leads Black Manta to the Black Trident. The weapon comes from an ancient Atlantis city, the Lost Kingdom in question, and there’s an entire story around it that’s gracelessly relayed too late in the film. What’s important to know is that whoever wields the spear makes a devilish pact. For the small price of their soul and eternal fealty, they can have their greatest dream fulfilled.

Lucky for the demonic spirit haunting Black Trident, Black Manta is focused. More ambitious villains might aim for world domination, but the guy who dresses like a bug is content with murdering Aquaman and everyone he loves. When Black Manta gets a hold of the Black Trident, he embarks on a mission that predictably jeopardises the future of land and sea civilisations.

With so much already on his plate, Aquaman knows he can’t save the world alone. Cue a fraternal reunion. Against weak protestations from everyone – including Nicole Kidman, returning as his mother – Aquaman teams up with Orm to save his family and the world.