Based on a novel by Lawrence Osborne, “The Forgiven” is sumptuously shot in Morocco, where a decadent party is being held in an American’s posh villa. David, a drunk self-contemptuous surgeon (played with biting force and growing poignancy by Ralph Fiennes), is driving to the festivities, with his wife Jo (Jessica Chastain is given little to work with), through the desert in the dark, when they hit a Moroccan teenager and kill him. The film then morphs into a morality portrait, when the boy’s ancient father arrives to retrieve the body. The Forgiven presents as two interwoven halves; in one, David journeys to find himself through his haze of privilege; in the other, writer-director revels in portraying loathsome morons behaving in repellent ways. The trouble is, the second portion contains no narrative tension at all, is just a backdrop that quickly grows tedious for the viewer. This could have been a fine film but ends up as an unsatisfying mixed bag.