Mute alien Joe Morton, a slave on his home planet, escapes to Earth and the vibrant streets of ’80s Harlem, where the locals’ initial bewilderment and hostility give way to camaraderie. Sayles, who plays an extra-terrestrial bounty hunter alongside David Straithairn, uses the trappings of science-fiction as a launchpad for this richly textured, drolly funny immigrant allegory.