However, secrets don't stay buried in Rosewood. When Alison’s mom returns to town in Season 2, Episode 6, “Never Letting Go,” for a charity fashion show honoring her daughter, her secret will be revealed. And according to Pretty Little Liars showrunner Marlene King, it’s a juicy one.
Marlene told E! Online, “Alison's mother and one of the Pretty Little Liars' parents have a secret too they've been hiding.” We’re guessing she had an affair with someone's father. Our money is on either Mr. Hastings (spoiler alert — they have an affair in the books), or Byron Montgomery (Chad Lowe), since he doesn’t have a good track record.
Maybe Ali’s mom had a child with another PLL parent and they’ve been hiding it all these years. OMG, two of the little liars could be stepsisters! What? It could happen.