Sarah Jane Smith realises that she and the Bannerman Road gang won't be able to defend the Earth forever, and an alien encounter may one day happen without their being able to do anything about it. She and Mr Smith start the Alien Files, a database of everything they know about the alien species they've dealt with, in hopes that it will remain as a resource for future generations. For her first upload to the Alien Files, Sarah Jane recounts her dealings with the Trickster and Krislok the Graske.