In “The Road to Guantanamo,” taped footage shows United States Secretary of Defense Donald Rumsfeld defending prisoner treatment in the Guantanamo Bay detainment camps as “consistent with the Geneva Convention for the most part.”The abyss of a gray area created by those last four words is what drives Michael Winterbottom and Mat Whitecross’ new film — and it is what kept three men tortured and terrified for nearly three years in real life.“Guantanamo” chronicles the experiences of Ruhal Ahmed, Asif Iqbal and Shafiq Rasul, British Muslims now known as the ‘Tipton Three.’ Shortly after Sept. 11, they traveled to Pakistan for a wedding, eventually traveling to Afghanistan. Fast-forward almost three years, and they are former suspected terrorists and prisoners, most notably in the notorious Cuban detainment camp that has come under fire with allegations of torture.With splicing reenactments, news footage and interviews with the real men, “Guantanamo” unfolds almost as a deathly grim black comedy, the men crossing from Pakistan to Afghanistan and continually finding themselves in the wrong place at the wrong time. In its consistently riveting story and masterful grip on its “docu-drama” form, it is one of the most skillfully crafted films of the year.Winterbottom, director of this year’s brilliant “Tristram Shandy: A Cock and Bull Story,” shoots the film’s first half with a hyperactive hand-held camera that captures the boiling daytime desert and surrealistic nights and does not shy away from the brutal interrogations, subjugation and beatings that ensue once the men enter the hands of U.S. forces.“Guantanamo” is so harrowing and infuriating, it is almost easy to miss its crater-sized hole. The Tipton Three say they traveled to Afghanistan “to help out,” an ambiguous — and arguably questionable — excuse for venturing into a war-torn country. Winterbottom and Whitecross accept and pass over such a vague motive, never diving deeper, a move that does damage to the film’s otherwise strong effect. Lapses in clarity aside, what remains in “Guantanamo” is the assertion that there’s a zero-sum game being played in Cuba — a “Mission Accomplished ... for the most part” of sorts. And based on the damning statistics on the amount of Guantanamo detainees charged and found guilty, it is hard to argue.