Even though viewers know how this film will end, the writing is so good that the suspense builds pretty much constantly throughout the entire film. Acting and production values are excellent as well. The scenes between O'Neill and his wife were, for me, the weakest element; it just didn't ring true to me that he could keep her at such a distance throughout his difficult assignment. The final scene also struck me as a bit too melodramatic. But the rest of the film had me going for sure -- I'd give it four and a half stars for its genre.