After he witnesses a dazzling object in the sky research student Richard Jarman learns that part of the greenbelt around London has been destroyed ostensibly by fire Convinced that the UFO was responsible he tells the police who react with scepticism When he discovers that similar incidents have been occurring across the globe Richard becomes obsessed with discovering the cause He neglects his thesis & in his search for answers becomes involved with an elderly vagrant & a nun who both witnessed the same phenomenon Richard & the nun fall into the clutches of a shadowy religious cult whose terrifying leader believes that the destruction of the world's vegetation heralds the end of the world & the Second Coming of the Messiah The planet is plunged into even greater crisis when spaceships descend & a host of seemingly indestructible beings invade some of the world's most populous cities When Richard & his girlfriend Fiona consult a famous medium they believe they have discovered the motive for the invasion but is it the right one?