A false newspaper story of an alien sighting lures Sarah Jane and her young friends to an antique shop, whose mysterious owner tells them they must enter a time vortex and locate three separate articles from different periods of history to save the world. Clyde is washed up on the East Anglian coast in 1941 where he and evacuee George escape from a trio of invading Nazis using the object of Clyde's quest, an artefact known as Thor's Hammer, to activate their transmitter. Sarah Jane joins ghost-hunter Emily Morris in a haunted house in 1889, ending up in a room where voices lead them to believe that children will die in a fire in the future. Rani finds herself in the Tower of London with the imprisoned Lady Jane Grey, whom she saves from an assassination attempt with a jewelled dagger, which would appear to be what she is looking for.
