Most of the old gang (sans Thor and Bruce Banner) and a few new faces are present and accounted for in "Captain America: Civil War," the fully realized, character-centric crowd-pleaser 2015's lackluster, convoluted "The Avengers: Age of Ultron" never quite was. Returning to helm following 2014's superhero ode to '70s paranoid thrillers "Captain America: The Winter Soldier," Anthony Russo and Joe Russo pick back up without missing a beat, managing what Joss Whedon failed to achieve in "Ultron:" handily juggle an ever-expanding ensemble without losing sight of their established relationships and camaraderie. The Russos and screenwriters Christopher Markus and Stephen McFeely (2013's "Thor: The Dark World") also don't skimp on a quality storyline, one offering a politically and morally incisive debate (not unlike 2016's "Batman v Superman: Dawn of Justice") on the culpability of planet-saving superheroes in the wake of unavoidable destruction and human sacrifice.

When a battle against bioterrorists in Lagos ends in an accidental death toll at the telekinetic hands of Wanda Maximoff/Scarlet Witch (Elizabeth Olsen), the Avengers find themselves under increased scrutiny by the United Nations. The proposal of the Sokovia Accords—a legal document backed by 117 countries binding the Avengers to closer government supervision and great accountability for their actions—divides the team down the middle. Haunted by a chance run-in he has with the mother (Alfre Woodard) of an innocent victim who perished under his watch, Tony Stark/Iron Man (Robert Downey Jr.) is supportive of the legislation. While Natasha Romanoff/Black Widow (Scarlett Johansson), Lt. James Rhodes/War Machine (Don Cheadle), and philosophical humanoid Vision (Paul Bettany) join Tony in the pro column, Steve Rogers/Captain America (Chris Evans) is stridently against it, believing this increased control will ultimately hinder their duties. With Wanda, Sam Wilson/Falcon (Anthony Mackie), and newly unretired Clint Barton/Hawkeye (Jeremy Renner) backing Steve's cause, allegiances on both sides are formed as the threat of criminal penalties loom. Further complicating matters is a deadly bombing claiming the life of the peace-seeking leader of Wakanda, King T'Chaka (John Kani). Steve's former friend, the mind-controlled Bucky Barnes/Winter Soldier (Sebastian Stan), is suspected of the attack, but a sneakier foe in the form of string-pulling, vengeance-hungry Helmut Zemo (Daniel Brühl) waits methodically in the wings.

"Captain America: Civil War" gets off to a bumpy start with the opening Lagos action sequence displaying erratic camerawork, choppy editing and an overabundant use of Scarlet Johansson's obvious stunt person. It's all gratifyingly uphill from there as the diverse, by-now ingratiating personalities of the characters take over. Many of the actors left stifled by the clumsy, unfocused writing in "Age of Ultron"—here's looking at Chris Evans's (2014's "Snowpiercer") freedom-fighting Steve Rogers, Scarlett Johansson's (2016's "Hail, Caesar!") smooth operator Natasha Romanoff, and most notably Robert Downey Jr.'s (2014's "Chef") droll, emotionally plagued Tony Stark—return to their glory as they meaningfully interact with each other and are given their own personal viewpoints. The film, delving deeper into Tony's past and the loss of parents Howard (John Slattery) and Maria (Hope Davis), could just as easily have been the fourth "Iron Man" installment without a frame of footage having to be changed. Moreover, an early flashback to Tony's young-adult self may be the most stunning special effect of all, with Downey Jr. de-aged to look exactly as he did in his late-teens/early-20s.

By taking the time to further develop their protagonists, directors Anthony Russo and Joe Russo allow the viewers to see them as people and not just super-powered icons. A scene between Wanda and Vision where he attempts to cook for the first time, for example, has little to do with the central plot but is the sort of special observational touch that 2014's "Guardians of the Galaxy" had, setting it apart from the lesser, more by-the-numbers Marvel entries. The centerpiece set-piece everyone will be talking about—a mano-a-mano airport-set showdown between the squabbling heroes—is total fun in spite of its insignificance; for all their disagreements, they are still friends who wouldn't seriously harm each other. More provocatively enticing are the verbal debates igniting from both corners, the squad wanting to do what is best for the world while regaining the trust of citizens who have begun to perceive them as vigilantes rather than selfless good guys.

Also a rousing success are the key introductions of two new players who, in the coming years, will be receiving their own standalone features. Skepticism over a third actor in the span of nine years portraying a new incarnation of Peter Parker/Spider-Man (following Tobey Maguire and Andrew Garfield) vanishes in an instant as the immensely likable, youthful, genuine Tom Holland (2012's "The Impossible") walks onto the screen; he is fantastic, and so is Marisa Tomei (2015's "Love the Coopers") in her brief appearance as Aunt May. Also mightily impressing is Chadwick Boseman (2016's "Gods of Egypt") as Prince T'Challa, the grieving, embittered son of the ill-fated King T'Chaka. Boseman charismatically embodies this role with hints that much, much more is yet to come with him. If any subplot suffers as a result of so much going on, it is T'Challa's evolution into Black Panther (Chadwick Boseman). Without warning or explanation, he pops up in costume, able to claw his way down buildings and jump from one moving vehicle to the next as if he's been doing it forever.

For a film with a daunting amount of ground to cover, "Captain America: Civil War" never feels overstuffed. Exhibiting command, focus, a spright rhythm, and more on its mind than the next obligatory fight or explosion, the Russos ensure the picture never lags throughout its 147-minute running time. Even head villain of the piece Helmut Zemo, played with a magnetic, low-key intensity by Daniel Brühl (2013's "Rush"), is given more unsuspecting layers than one might expect without having to slow the pace. The inaugural chapter in Phase Three of the Marvel Cinematic Universe, "Captain America: Civil War" has been made with a clear-cut vision and a reverence for its broadening mythology. As long as talented, passionate filmmakers continue to be brought aboard to take these stories and characters in fresh directions, there is no reason to expect this massive franchise will grow stale or lose its vitality anytime soon.