Early in the extraordinary documentary “Flee,” its subject – known by the pseudonym Amin Nawabi – is asked to define the word “home.” Lying back on a tapestry-covered day bed, his eyes closed, he replies, “It means someplace safe.” Danish filmmaker Jonas Poher Rasmussen creates a movie as a safe space with “Flee,” in which he draws Amin out to reveal the most intimate and haunting secrets of his life.

The two became best friends as teenagers when Amin emigrated from Afghanistan to Denmark, a journey that quickly became mythologized among their peers as having been accomplished entirely on foot amid tragic circumstances. As “Flee” opens, Amin has remained silent about his past for 25 years until agreeing to let Rasmussen put him on the couch.

The result is a mesmerizing story of loss, dislocation and, yes, tragedy, but also self-invention. At a time when news stories about refugees and migration threaten to become numbingly anonymous, “Flee” restores the fine detail and human contours that make each version unique, individual and vital.

Now might be a good time to add that Rasmussen does this almost entirely by way of animation: In a bold storytelling choice, the filmmaker – who got his start in radio – uses the audio portions of his interviews with Amin and sets them to beautifully drawn sequences that quickly become just as immersive and evocative as live-action film.

Interspersing Amin’s memories with vintage newsreel footage of daily life in Kabul and Moscow (an important way station in Amin’s journey), Rasmussen creates the aesthetic distance Amin needs finally to tell his truth, about which he’s understandably guarded, for reasons that become clear.

He also engages in the kind of world-building that cinema is made for, allowing viewers to free their own imaginations to enter another person’s consciousness and feel, firsthand, what it might be like to live in their reality. In Amin’s case, that reality is a relatively idyllic childhood that comes to an abrupt end when the Soviets invade and then leave his country; the subsequent years are filled with uncertainty, grief, glimmers of hope and, finally, a distinctive survivor’s guilt.

There are moments when “Flee” resembles a kind of modern-day “Sophie’s Choice” with its intimations of moral injury and the will to survive. Rasmussen seamlessly interweaves the trauma that animated Amin’s teenage years and young adulthood with his current ambivalence about marrying his longtime partner, Kasper.

Joining filmmakers such as Josh Oppenheimer and Robert Greene, Rasmussen uses the filmmaking process itself as a form of therapy, which would be scandalously self-indulgent if he didn’t approach “Flee” with such judiciousness and surgical skill.

Brilliantly linking the film’s disparate visual elements (the animation changes to tone-on-tone chiaroscuro when Amin’s recollections become particularly fraught), adding vocal re-enactments where necessary, Rasmussen creates one of the most vivid onscreen stories and characterizations in recent memory.

Amin’s story is often terrifying, from the desperation and physical dangers he endures to the bleak portrait of human nature that emerges from the people who have exploited and ill-treated him along the way.

But “Flee” winds up being improbably exhilarating, as Amin begins to own his full story and, by extension, that story’s most harmful chapters begin to loosen their hold on his psyche. Thanks to his courage and Rasmussen’s compassion and creativity, “Flee” morphs from a tale of dispossession to a testament to the power of narrative – to overtake a life and to liberate it.