In 1916, botanist Dr. Lily Houghton (Blunt) is trying to locate a legendary plant known as Tears of the Moon, a tree whose petals are purported to have incredible powers. Many have been lost in its pursuit, including an expedition by the Spanish conquistador Aguirre (Edgar Ramirez, “Yes Day”) back in the 16th century; Aguirre’s actions resulted, according to the tales, in a longstanding curse.

Houghton has gotten her hands on an artifact that she believes is the key to finding the Tears of the Moon; she enlists her uptight brother MacGregor (Jack Whitehall, TV’s “Good Omens”) to join her on a trip to South America in a quest to find the Tears of the Moon, proving their late father’s theories. The Houghtons aren’t alone in their quest, however; the eccentric and unsettling Prince Joachim (Jesse Plemons, “Judas and the Black Messiah”) – third son of Kaiser Wilhelm – also seeks the Tears of the Moon, though not for the same altruistic reasons.

Upon their arrival, the Houghtons must hire a boat. A confluence of standard goofy Disney-style circumstances lands them with Frank Wolff (The Rock), a small-time skipper who ekes out a meager living giving river cruises to tourists. Wolff is struggling, in debt to the area’s primary boat operator, the sleazy Nilo (Paul Giamatti, “Gunpowder Milkshake”). Despite some early conflict, Lily decides to hire Frank to help her with her search.

(“Early conflict” – I’m guessing you know the drill with regard to how THAT plays out.)

Of course, it isn’t as easy as all that. The trio face threats both natural and supernatural as they make their way up the Amazon on a journey that may ultimately prove futile, even as a variety of enemies plot against them. For there are those who will stop at nothing to gain control of the Tears of the Moon, no matter who they might have to destroy along the way.

As far as IP cash grabs go, “Jungle Cruise” could have been worse. It could have been a lot better, mind you, but it could have been worse. There’s a charm to this sort of freewheeling adventure movie, even if it is overladen with often-obvious CGI effects. Even with the slightly more adult rating, this is essentially a movie for kids, though it does make some vague efforts at appealing to older audiences.

And there’s nothing wrong with that – it is Disney, after all.

The truth is that there are some rather appealing aspects to this film. My personal affection for The Rock is well-documented at this point, and this movie is a good fit for him – he excels in these situations where he’s not asked to do much more than let his natural charisma shine. He’s got some jokes, he’s got some action – it’s his wheelhouse. And it’s a surprisingly good match with Emily Blunt; she’s perhaps not his typical co-star, but she’s plenty charming in her own right and the two of them have a screwball comedy dynamic that goes a long way to compensating for some of the movie’s narrative flaws. Basically, the plot is thin, but you don’t care as much because these two are fun to watch.

That said, you care a little. The story meanders hither and yon without much urgency; the film’s 127-minute runtime could have easily been shaved by 10 or 15 minutes. There are spots where the film feels padded, as though someone in an office somewhere demanded at least two hours. Something more streamlined might have been more effective.

One place where that streamlining might have helped is to remove some of the nigh-ubiquitous CGI. I understand both its utility and necessity for a film like this, but there are at least a handful of overly-produced moments that simply fall flat because of that technological overreliance.

But again, Blunt and The Rock help carry the day. Whitehall is also very good, lending his own particular goofball charm to the proceedings. Plemons continues his tendency to play oddballs and weirdoes, much to this film’s benefit; he’s both low-key and over-the-top here. Ramirez largely plays it straight, even as his assorted compatriots camp it up; it’s a good choice. Giamatti is clearly having a blast with his own oddly-accented sketchiness.

No one expects great cinema from a film like “Jungle Cruise.” It’s a movie based on a theme park ride – you’re not going to get “Citizen Kane.” But for those who like popcorn-munching adventure fare, you could do worse, particularly when you have a central pairing like The Rock and Emily Blunt bantering and brawling their way through the film’s center. It’s fun, and sometimes, that’s all you need.

[3 out of 5]