Question: when did alison go missing in pretty little liars

title: Alison DiLaurentis
text: Alison Lauren DiLaurentis is a fictional character and main antagonist in the Pretty Little Liars novel series , introduced in the original series of novels and also appearing in the television adaptation . In both the beginnings of the books and television series , Alison is a central character who is shown mostly in flashbacks . The entire plot of the series begins when Alison mysteriously disappears and leaves the small town of Rosewood in shock . Due to her position as a queen bee of Rosewood 's social scene , Alison 's actions and relations are constantly under scrutiny from the town 's citizens . Sasha Pieterse , who portrays the character on screen , has described Alison as an indecisive person , even showing herself as a ruthless , manipulative girl . 

Answer: answer: Alison Lauren DiLaurentis is a fictional character and main antagonist in the Pretty Little Liars novel series. The entire plot of the series begins when Alison mysteriously disappears.