Log Line Ideas For Opening Sequence

Log lines must provide enigma (generating questions in the audiences mind), establish a main character and possibly location as well as the overall purpose/aim of the film/

'The Dark Knight of Gotham City begins his war on crime with his first major enemy being the clownishly homicidal Joker.'

For example the above presents the log line to 'Batman' (1989) in which main character, location and purpose of the films content is established. 'The Dark Knight' being Batman, 'Gotham City' establishment of location and 'his war on crime with his first major enemy' establishes the films purpose, the log line also presents the antagonist 'The Clownishly homicidal Joker'. With all of this in context as sense of enigma is created, why is 'The Dark Knight' at war with crime, what is the purpose of the antagonist etc.