EXCLUSIVE TO YOU IN YOUR CITY   BEGINNING OF A SEARCH -- Stuart Damon, Alexandra Bastedo and William Gaunt, in their series roles as agents of Nemesis, look for clues in a warehouse, in “The Ghost Plane” which will be colorcast on “The Champions” Monday, June 24 (8-9 p.m. NYT) on the NBC Television Network.   (C)   NBC-TV CAPTION SUBJECTS:     (from left) Stuart Damon, Alexandra Bastedo and William Gaunt PROGRAM:     “The Ghost Plane” -- episode on “The Champions” TIME:     NBC Television Network colorcast, Monday, June 24 (8-9 p.m. NYT)