Various shots of DEW (Distant Early Warning) line "Beachhead" in Canadian Arctic. Several shots of cranes at work, of landing craft, tractors, amphibious craft, supplies, trucks. Sequence showing prefabricated buildings being assembled with tractors and cranes. Shot of group of underwater divers paddling rubber raft furiously towards camera, clambering out. Shot of sea as explosion occurs. Shot of frogmen paddling away again. Shot of other explosion of underwater charge. BOATING LSs of freighter anchored some distance offshore, of landing craft speeding towards land. Closer shots of freighter as camera boat sails around her bow.