Aliens are preparing to invade earth, but first they need to check for danger. They have sent out their best people to asses the risks of both fully grown and young humans. The threat posed there was practically non-existent. The only remaining possible obstacle to their dominion are the beings they have no knowledge of, the Teenagers. Disguised as one of these mysterious Teenagers, agent A-3266 has been sent to earth on a reconassaince mission. To fit in to this disguise, all mission reports are in the form of what the humans call a 'diary'. Will these Teenagers pose a threat to the invasion, or will they be as weak as the rest of the human race?