Some of the glowing ones also become feral (or some of the feral ghouls start to glow due to exposure to radiation). They are known to use radiation-based attacks on humans.
The game takes place in the year 2277 on the East Coast of what used to be the United States of America. The player character, known as the Lone Wanderer, is a young inhabitant of Vault 101, a fallout shelter in the Washington D.C. area. The vault has reportedly been sealed for 200 years, until the player's father, James, opens the only door to the outside world and disappears without any explanation.