Consequences

One week, I was unable to go, which had unforseen consequences.
A's mother, brooding about what we were "getting up to" - (which amounted to revelling in the beauty, the isolation) - had evidently come to the conclusion that I, the girl whom she didn't know, must be "good".
She made a surprise swoop on the little shack.
That I, the good girl, was not there proved that the other three were bad: why else would I stay away?
Having proved that the three were bad, therefore confirmed her opinion that I was good.
Q.E.D.
A was a lovely, serene girl; immersed in poetry and history and literature. She endured her mother's mental illness with such grace and kindness and good temper. I don't know how she did it.