Ben Affleck’s Argo begins with a commonly seen notice that’s often proven drearily frivolous: “Based on a true story.” In Argo’s case it’s more meaningful than has usually transpired. It begins a movie that delivers both (substantially) factual material and a solidly carpentered and exciting political thriller.

Argo relates the true-life story of the rescue of six Americans who escaped from the American embassy in Tehran as it was overrun and its staff was taken prisoner by a mob of enraged Iranians on November 4, 1979. (Affleck and scripter Chris Terrio provide a brief prologue that summarizes the quarter-century of US and British neo-imperialist political interference in Iran that fed the mob’s fury.)

The six escapees were secretly given refuge in the Canadian embassy and a tensely perilous situation ensued. The Canadian and American governments anxiously awaited the Iranian government’s inevitable discovery of the hiding place. (The rest of the embassy staff was held hostage for 441 days.) Both countries desperately cast about for a means to extract these six people from Tehran.

The very unlikely “best bad solution” was proposed by Tony Mendez (Affleck), a practiced CIA black-ops agent. It was almost ridiculously redolent of pulp fiction: Pretend to be a Canadian scouting Tehran for movie-shoot locations and take the six out as members of the crew of the imaginary film. Because Argo is fundamentally accurate—the real Jimmy Carter, president while all this happened, provides an eventual validation of the movie—it has a moral heft and high-stakes charge that most espionage movies can’t match. But much of its intensity and, yes, its entertainment value come from the smart script and Affleck’s smooth direction.

In his third directorial effort, it’s apparent that Affleck has become a very proficient, incisive director. The early mob invasion of the embassy is kinetically frightening and convincing. Affleck shows a real grasp of pacing, cross-cutting, and shot selection. Like other actor-directors, he’s good with cast members. John Goodman is mordantly cynical as a Hollywood costume designer who dabbles in spycraft. Bryan Cranston (TV’s Malcolm in the Middle and Breaking Bad) at last has a movie role that’s worthy of his often misused talents. And Alan Arkin, the veteran exemplar of offbeat scene stealing, gives a little gem of a performance as an over-the-hill producer fronting as the fake movie’s executive authority. If there’s a weak spot, it’s Affleck himself, who sometimes seems too stolid amid all the flux and fear. But his occasional appearance of detachment doesn’t derail this powerful package of a movie.

Watch the trailer for Argo