2014's Michael Bay-produced "Teenage Mutant Ninja Turtles" was undemanding popcorn silliness, far from a critical darling but certainly a step above its clunkier, murkier 1990 incarnation. For all its leaps in logic (and what else would a person expect from a fantasy-adventure starring four 6-ft.-tall heroes in half shells named after Italian Renaissance painters?), the film capably told its story with pleasing portions of involving action fireworks and heart. As intrepid young reporter April O'Neil, Megan Fox (2012's "This Is 40") proved herself to be a plucky protagonist with swift comic timing, portraying a character which thankfully asked more of her than to pose as archetypal eye candy. She, more so than the pizza-loving turtles, led the picture—a wise choice that brought an added levity to the goings-on than it otherwise might have had. In contrast, "Teenage Mutant Ninja Turtles: Out of the Shadows" is soulless, by-committee tripe, director Dave Green (showing such promise with 2014's "Earth to Echo") and screenwriters Josh Appelbaum & André Nemec (2011's "Mission: Impossible - Ghost Protocol") concocting an unctuously busy follow-up that never takes a breather long enough to concern itself with the people—humans as well as reptiles—involved.

One year ago, crime-fighting adolescent turtles Leonardo (Pete Ploszek), Raphael (Alan Ritchson), Donatello (Jeremy Howard) and Michelangelo (Noel Fisher) saved New York City from the dangerous Foot Clan syndicate, tidily putting away nefarious leader Shredder (Brian Tee) in the process. Afraid of revealing themselves to the public, they made a deal with April's news cameraman Vernon (Will Arnett) to take the credit. As his fame level has risen in the aftermath, the brothers have stood by stealthily in the shadows, waiting for their chance to once again come to the rescue. That time arrives when an undercover April learns mad scientist Baxter Stockman (Tyler Perry) is in cahoots with the Foot Clan to break Shredder out of prison. This is but the first step in an evil master plan involving Baxter's teleportation device, a slimy alien named Krang (voiced by Brad Garrett), a canister of ooze with transformative DNA powers, and the retrieval of three artifacts with the collective ability to open a portal and bring about the end of civilization. Aiding in April and her pals' mission is vigilante-in-training Casey Jones (Stephen Amell), a recently fired corrections officer who witnessed Shredder's otherworldly escape.

"Teenage Mutant Ninja Turtles: Out of the Shadows" places its title foursome squarely in the lead roles—a notion that makes more sense on paper than in actuality. While a half-hearted attempt is made to individualize them in lazy ways (e.g., introducing each of them with screen credits labeling Leo as "The Leader," Raph as "The Muscle," Don as "The Brains," and Mikey as "Pizza Eater"), their internal squabbles over whether or not to reveal themselves to the world above the sewers is as deep as any of them get. Simply put, they aren't interesting or engaging enough to carry a 112-minute feature. With the turtles taking center stage, Megan Fox has seen her part downgraded to a virtual afterthought. Writers Applebaum and Nemec pay April so little attention it is never even clear until the final scene whether she is still a news reporter or a self-employed investigator. With nary a second devoted to her life outside of the movie's main plot, it almost appears as if she has unsettlingly moved into the sewers with the turtles and their Zen-like rat master Splinter (voiced by Tony Shalhoub).

As is often the case with sequels, a very clear attempt has been made to go bigger and more bombastic, with increasingly wearisome results. The narrative is choppy nonsense, with characters hopping around with little regard to basic elementary coherence. Action set-pieces are uninspired and familiar, right down to ill-placed waterfalls and a swirling apocalyptic city sky. As all hell breaks loose outside, April, Vernon and Casey are forced to meander around a warehouse with the urgency of people walking to their mailbox. In the grand tradition of Skids and Mudflap from 2009's "Transformers: Revenge of the Fallen," Shredder's henchmen are stereotypical prisoners Rocksteady (Stephen "Sheamus" Farrelly) and Bebop (Gary Anthony Williams), turned into a wisecracking rhinoceros and warthog, respectively, while trading flatulence and cheering on the girth of their new jumbo-sized penises. Their shtick is painful from the start and only grows more interminable by the minute.

With the exception of the charismatic Stephen Amell (TV's "Arrow") as Casey Jones, every actor in "Teenage Mutant Ninja Turtles: Out of the Shadows" looks bored. Who could blame them? Megan Fox might be a better actor than some give her credit for, but she isn't a good enough liar to hide her disinterest in this thankless material. Her only notable moment is accidental; sporting a blonde wig in her first scene, the naturally brunette performer bears an uncanny resemblance to Rachel McAdams. Looking like an unhinged Neil deGrasse Tyson, Tyler Perry (2014's "Gone, Girl"), as scientist Baxter Stockman, embarrassingly spouts highly intellectual lines such as, "Eliminate those turtles!" Above everyone else, however, it is Laura Linney (2013's "The Fifth Estate") whose beyond-awkward appearance is most worthy of discussion. Playing Rebecca Vincent, the all-business captain of the Bureau of Organized Crime, Linney clearly cannot believe she has found her way into a movie called "Teenage Mutant Ninja Turtles: Out of the Shadows." Short of being forced to stand silent and immobile in a corner, she couldn't have less to do. No matter what she is saying, her eyes seem to be pleading for help. Even when she finally smiles at the end and offers congratulations to the heroes, it is done through gritted teeth. Her disdain for this project is not only plainly obvious, but, as it turns out, wholly warranted.