In Marvel Cinematic Universe terms, it's all been leading to this. Positioned as the epic finale to an interconnected series of twenty-two films beginning with 2008's "Iron Man," "Avengers: Endgame" traverses a startling amount of territory in an enrapturing and—all things considered—economical 182 minutes. Said territory, however, will likely not match up with what most dedicated viewers will be expecting. This is key to the giddy ingenuity directors Anthony Russo & Joe Russo and screenwriters Christopher Markus & Stephen McFeely (the four returning for duty following 2018's "Avengers: Infinity War") have cooked up, all previous trailers and advertising barely hinting at the narrative twists and turns and the oft-surprising places the exorbitant ensemble of characters find themselves. Indeed, in a eagerly awaited blockbuster such as this, it is crucial to retain the secrets held within—a challenge for any writer endeavoring to review the picture, but also a necessity.

The unsettlingly bleak conclusion of "Avengers: Infinity War" found Thanos (Josh Brolin) successfully collecting the six Infinity Stones, elemental crystals which, with the snap of his fingers, obliterated half the universe's population. The surviving Avengers—among them, Tony Stark/Iron Man (Robert Downey Jr.), Steve Rogers/Captain America (Chris Evans), Thor (Chris Hemsworth), Natasha Romanoff/Black Widow (Scarlett Johnansson), Bruce Banner/The Incredible Hulk (Mark Ruffalo), and new addition Carol Danvers/Captain Marvel (Brie Larson)—cannot accept this cruel fate. Thanos' daughter, Nebula (Karen Gillan), out for vengeance for the murder of sister Gamora (Zoe Saldana), knows where her father is hiding. Retrieving the Infinity Stones in his possession is their only hope in reversing course and making things right.

The opening fifteen minutes of "Avengers: Endgame" follow a more or less expected setup for the adventure to come, only for the proverbial rug to be pulled out from beneath all involved (audience included). To discuss in any specific detail where the next 160 minutes go would be an indictable offense, but suffice it to say, there are genuine reactions of shock to be had and a level of imagination offered that arguably surpasses all previous features within the MCU. If "Avengers: Infinity War" played like one extended, seamlessly designed action sequence, "Avengers: Endgame" blasts off with forward momentum but isn't afraid to slow down on occasion to delve deeper into the emotion and psychology of superheroes who feel as if they've let the world down. All of the central actors here—the ones who were not turned to dust at the end of "Infinity War"—are given some of the meatiest material they've yet had within this series, their fallibility and, by extension, vulnerability highlighted with richly rewarding writing and note-perfect performances delivering upon the enormity, consequence and finality of this project.

Despite an understandably sobering throughline, the proceedings are not merely a study in doom and gloom. Another pleasant surprise is how much natural humor evolves from the material, particularly as the story is forced to recalibrate before the first act is up. The middle hour, commenting on and revitalizing the tropes of a subgenre which shall remain nameless, organically and gloriously pays tribute to many of the past installments of the MCU while recalling key supporting players and incidents. The pacing here threatens to lag a time or two, but is fortunately never more than moments away from taking off again. As for the spectacularly crowd-pleasing climax, it reminds of the airport-set battle in 2016's "Captain America: Civil War" times a thousand, said fight carrying a dramatic weight and cohesively swirling satisfaction heretofore unequaled in this franchise.

Here today, gone tomorrow. It's a reality which everyone must face as the hands of time tick by, and not even the Avengers are immune to its cruel inevitability. "Avengers: Endgame" is a cathartic powerhouse, providing bittersweet closure rather than a finite ending to an impressively voluminous superhero saga. Life and legacy, after all, must go on. As one thinks back on what has transpired after the fact, it's startling how exquisitely crafted each element is. Juggling a potentially unwieldy cast and complex but always entirely coherent plotting, the film pays off again and again in dramatically honest ways while never feeling rushed or bloated. A lot has been riding on this grand conclusion to the first three Phases of the Marvel Cinematic Universe; like a methodically lined-up set of dominoes, one wrong move could send everything topping down. "Avengers: Endgame" not only pays off in nearly every conceivable respect, but frequently surpasses one's loftiest hopes. For casual fans, it's the can't-miss event of the season. For die-hards, it earns its spot as the can't-miss event of the decade.