Good news: there’s no expensive “de-aging” process used in “Da 5 Bloods,” Spike Lee´s absorbing, brash, exhausting, urgent, sometimes brilliant and sometimes unapologetically messy new film about four black Vietnam vets who return to the battlefield site for reasons … well, we´ll get to the reasons. Lee says there just wasn´t enough money in his Netflix budget for such a costly special effect, a la “The Irishman,” even though it would have helped with the flashbacks. But honestly, with Spike Lee, do you really need special effects? Isn´t Lee´s own propulsive energy, inexhaustible creativity and blazing sense of purpose an effect in itself? To that, let’s add a sense of exquisite timing. Yes, Lee has always had good timing. But it´s never been more evident or important than with the release of this film amid the current national reckoning over racial justice and police brutality. “Time has come today,” goes the Chamber Brothers song that accompanies Lee´s trailer. And: “Can´t put it off another day.” Indeed. You´ll find yourself awed by Lee´s prescience only moments into the film, with a searing montage of archival footage setting the Vietnam War, and most importantly the experience of black soldiers in that war, into political and social context. Activist Bobby Seale, in one 1968 clip, recalls how blacks served in the Civil War and then World War II, with freedom still elusive, “and now here we go with the damn Vietnam War and we still ain´t getting nothing but racist police brutality, et cetera.” Lee, still on a roll after his overdue Oscar win for the terrific “BlacKkKlansman,” made a crucial change to the original story by Danny Bilson and Paul DeMeo. He and co-writer Kevin Willmott changed the band of aging Vietnam vets from white to black. Lee wanted to make that sorely missing Vietnam film in which black soldiers weren’t just a side story, but THE story. The original idea had the vets returning for a cache of buried gold. Here, they´re looking for gold, yes, but also the body of their revered squad leader, “Stormin´ Norman,” the fifth Blood and their hero, played with movie-star charisma and classic war-movie grit by Chadwick Boseman. Film buffs will find references to John Huston´s “The Treasure of the Sierra Madre” and Frances Ford Coppola´s “Apocalypse Now,” among others. In fact, it´s at a bar called “Apocalypse Now” – a real one – in present-day Ho Chi Minh City that the four Vets have a boozy evening before setting off into the jungle. Over drinks, the 60-somethings discuss what it was like to return from an unpopular war and be derided as “baby killers,” along with having to face the racial discrimination their white counterparts didn’t. The angriest of the bunch is Paul (a dynamic Delroy Lindo), who’s become a Donald Trump supporter and wears a MAGA hat. He also has a flawed relationship with son David (a terrific Jonathan Majors) who shows up at the last minute to join the expedition. There´s also the jovial Melvin (Isiah Whitlock Jr.); Otis (Clarke Peters), who has a crucial reunion with a former lover; and Eddie (Broadway star Norm Lewis), the genial owner of a car dealership empire who is clearly hiding something behind that Broadway-wattage smile. With help from a shady figure in international exports (a suitably slimy Jean Reno), the men head off in a riverboat to Wagner´s “Ride of the Valkyries” (a clear “Apocalypse” reference). They soon come across the buried gold, but there´s more to be discovered – and a whole heck of a lot to go wrong. In its latter parts, the movie sags a bit, or at least veers into more impressionistic, less disciplined territory. The men are not alone in this saga. There´s a group of land-mine locators, a band of Vietnamese officers, a tour guide, and that former lover, all of whose intentions remain to be determined. Then there´s the crazy heat, the poisonous snakes, the murderous unexploded mines. It´s a lot to absorb. But absorbing it is.