on this sunday night, nuclear deal. a historic agreement is reached with iran that president obama says will make the world more secure. >> for the first time in nearly a decade we have halted the progress of the iranian nuclear program. also the fallout as others in the region question whether iran will live up to its end of the bargain. massive storms, snow and ice take a deadly toll in the southwest. tonight it is on the move and threatening to disrupt holiday traffic for tens of millions. tis the season to shop. as retailers lure you in earlier and earlier, are the deepest discounts yet to come? and special bond. the young boy with autism and his dog. how they rescued each other and are making a difference with their message.