After a fleet of more than 250 police officers caravanned 700 miles from Burlington, Mass., to Lynchburg, Va., they were told they might not be able to complete their Christmas mission.

The convoy of cruisers, which stretched for 3 miles, went to Lynchburg bearing gifts for 5-year-old Nathan ­Norman, who suffers from a rare form of brain and spinal cord cancer. The boy had asked for cards from his heroes, police and firefighters, and 80 agencies were happy to grant his wish.