You don’t go to a “Teenage Mutant Ninja Turtles” movie expecting enlightenment, and you certainly won’t get any from this latest CGI-live action extravaganza from Michael Bay, who gave us not only the 2014 opening salvo in this series but the “Transformers” franchise as well. Reportedly the original subtitle for this installment was to be “Half Shell,” which was doubtlessly changed to “Out of the Shadows” to avoid people referring to it as “Half-Witted.” That proves one of the makers’ more intelligent decisions.

Anyway, after a prologue showing the pizza-loving quartet—motion-captured Michelangelo (Noel Fisher), Leonardo (Pete Ploszek), Donatello (Jeremy Howard) and Raphael (Alan Ritchson)—enjoying a Knicks game from the stadium rafters, what passes for plot kicks in as friend-of-the TMNTs, intrepid investigative journalist April O’Neil (Megan Fox, again doing duty as eye candy in Michael Bay product), looks into the plans of goofy scientist Baxter Stockman (Tyler Perry, giggling regularly as a sign of his dorky madness) to help the evil Shredder (Brian Tee) escape police custody. But that’s merely the beginning of the villains’ scheme to open a portal that will allow an alien invasion of earth, led by a grotesque blob called Krang (Brad Garrett), who aims to destroy humanity.

Before long April enlists the Turtles in her mission, along with Casey Jones (Stephen Arnell), a New York corrections officer who’s transporting Shredder when he escapes with Stockman’s help. Also joining the group in due course is Vern (Will Arnell), the cowardly cameraman who got all the credit for the Turtles’ heroics in the previous movie. On the sidelines is the NYPD’s top cop Rebecca Vincent (Laura Linney, slumming the way good actors do when handed lucrative supporting parts in stuff like this).

Meanwhile the nefarious plot against earth proceeds apace. Shredder gets a couple of henchmen in Bebop (Gary Anthony Williams) and Rocksteady (WWE wrestler Stephen “Sheamus” Farrelly), who are transformed via alien technology into a talking rhino and warthog. Ultimately they, along with Shredder’s right-hand lady Karai (Brittany Ishibashi), assemble the device that allows the portal to open and Krang’s forces to come through. Happily (or not, if you’re inclined to boredom—this drags on for nearly two hours), the assembling of his destructive ship gives the Turtles time to mount an assault against him while Jones faces off against Bebop and Rocksteady and April and Vern against Karai to close the portal. The back-and-forth cutting from one confrontation to another forms a big brawl montage to close the picture.

While all the action hubbub—car chases, assaults on airplanes in flight, battles in alleyways and warehouses and atop tall buildings—proceeds, much of the downtime is devoted to bickering among the brothers until, under the tutelage of their wise mentor rat Splinter (voiced by Tony Shalhoub, but used very sparingly here), they learn to appreciate one another’s different talents and work like a true team. This, we are informed, represents their maturation.

But if the Turtles are growing up, everything else about “Out of the Shadows” remains relentlessly juvenile. New director David Green and editor Bob Ducsay manage to keep what’s happening a bit more coherent than was the case in the first go-around, but their efforts are impeded by the frankly nonsensical script by Josh Appelbaum and Andre Nemec, and though cinematographer Lula Carvalho maintains a semblance of order in the compositions, the avalanche of CGI and big action sequences leave a lot of the footage looking messy, especially with the darkening effect of 3D. Steve Jablonsky’s score is the usual bombastic muddle, especially when heard at ear-splitting volume in an IMAX venue. (The regular 2D format might be preferable in this case.)

Of course the acting is inconsequential. The sole item of note in that respect—apart from Perry’s loony performance—is Arnell, whose effort to act macho is undermined by a squeaky, high-pitched vocal delivery and smarmy smile. It may be noted that his character prefers to fight using a hockey stick and puck, tossing the latter into the air and then hitting it to strike his opponents straight-on. It’s a technique that isn’t much different than what he does on TV, except there he employs a bow and arrow. It also requires him to wear a mask, which allows for a convenient substitution of a stuntman whenever the action gets a mite too dangerous.

This second installment in Bay’s latest franchise is mindless junk, but it’s pretty much on par with its very successful predecessor, and so should satisfy fans of that movie—whoever they were. Everybody else can be forgiven for thinking that turtles might be more enjoyably encountered in a bowl of soup.