British police have arrested at least 21 people in an alleged plot to set off "multiple explosions in multiple planes" headed from London to the United States. On official described the plot as "mass murder on an unimaginable scale." Airports all over America are on "Orange" or high alert" and almost all liquids are banned from carry-on luggage. For airports where planes are arriving from Britain, the level is "Red." Reaffirming that the US is safer than it was before September 11, President Bush today acknowledged that there are still those who would plot against the American people. It's reported that he and British Prime Minister Tony Blair talked about the conspiracy by telephone this past weekend. Blair is vacationing in the Caribbean. We go to London to update the plot and the plotters and hear what it's going to be like to travel at the height of vacation season.