|Pretty Little Liars character|
Sasha Pieterse as Alison DiLaurentis
Pretty Little Liars (2006)
|Created by||Sara Shepard|
|Portrayed by||Sasha Pieterse|
|Occupation||High school student|
Alison had been best friends with Hanna, Aria, Spencer, and Emily before disappearing the night of September 1st, 2009. She was the "It Girl", "Diva", and the Queen Bee of Rosewood High School up until her disappearance. One year after her disappearance,they say it was Alison's body was found buried in the backyard of Maya St. Germain's house. The autopsy states that she suffered a blow to the head and subsequently suffocated to death, with dirt being found in her lungs. The item that was used to hit her was supposedly a shovel, which was also used to bury her. A flashback is shown in This Is A Dark Ride of her hand coming out of the ground of her backyard, made for a gazebo. It is later revealed someone helped her out of the ground.
In "A Dangerous GAme" it is revealed that Alison is alive as she takes on the person of Red Coat - the leader of the The "A" Team. Her current existence ultimately raises a number of questions, especially concerning the body that was discovered in the Pilot episode. However, it is strongly speculated that Alison's existence still remains to be ambigious as Mona claims that Red Coat appears to look just like Alison.
Season 1 
In the episode "Pilot", The series begins with footage of the night Alison DiLaurentis disappeared. Alison, Aria Montgomery, Spencer Hastings, Hanna Marin and Emily Fields were having a sleepover party in Spencer's barn. Alison scared them by sneaking up on them in the barn doorway, causing them all to laugh. Aria, Hanna and Emily later wake up from their sleep and realize Spencer and Ali are both missing. Spencer then returns to tell the other girls that she looked for Ali everywhere and thinks she heard her scream. Aria has a flashback to October 2008 when she and Alison had cruelly ditched nerdy Mona only to find her father, Byron, kissing another woman inside his car. Spencer flashes back to a moment the summer before, when Melissa Hastings was dating then-boyfriend Ian Thomas. She had been standing with Alison and Hanna in her kitchen when Ian and Melissa walked in. Suddenly, Alison announced that Spencer had something to reveal, but Spencer denied it, and was annoyed by Alison's blunt betrayal. Outside, out of earshot, Ali had threatened to expose Spencer's secret in front of her sister, namely the fact that she had once kissed her sister's boyfriend Ian. Spencer had countered with a threat to expose Ali's involvement in "The Jenna Thing". After the flashback, Spencer looks out the window and sees into the window of Alison's house across from hers, a wavy blonde figure moving about inside. Spencer gasps, "Alison."
In the episode "The Jenna Thing", Alison reveals to the girls that she believes Toby Cavanaugh is spying on them while they were trying on clothes in Emily's room, and has been for some time. Alison immediately hatches a plan to drop a stink bomb in his garage as revenge. Emily and Aria try to back out, while Hanna and Spencer also share their reservations, but Ali is adamant that Toby must be taught a lesson. Alison then orders Spencer to pass the match and ignites the firecracker, opening the door of the garage, and tossing it inside. But the prank went terribly wrong when the garage catches on fire, and Alison sees too late that someone - Jenna Marshall - was inside. As a result, Jenna was blinded from the accident, and Alison made sure that Toby falsely took the blame for it. Alison had blackmailed him with a piece of information that Spencer could not overhear. While Emily is sitting by herself in a restaurant, she looks down at her bracelet and flashes back to the aftermath of "The Jenna Thing," when Alison had bought the other Pretty Little Liars friendship bracelets with their names on them. Alison had given the girls the bracelets in the same restaurant in which Emily is now sitting. At the time, she had even suggestively asked Emily to tie hers for her, indicating she knew Emily's secret.
In the episode "To Kill a Mocking Girl", Hanna is being interrogated by Detective Wilden, who suspects Hanna of having tried to kill Alison out of jealousy. She assures him that nobody tried to compete with Alison, that it was pointless, and thus in turn prompts her memory of the time in her chubby days when she asked Sean out to a party. She had asked him with a nervous, quavering voice, and Alison had stepping in, pointing out that everyone was going. She made eyes at him, and he accepted, perhaps because he really found Hanna charming or perhaps because Alison had been hard to resist. At Noel's cabin party, Spencer suddenly recalls the night of "The Jenna Thing," when the girls had to deal with the aftermath. Alison had been standing in front of the Cavanaugh house, blackmailing Toby with something to get him to take the hit for the fire in the garage. Spencer had walked over to listen, and Alison angrily pushed her back, angry that she violated her order to stay away. She follows Spencer to where the other girls are standing and tells her friends that she would have not set off the bomb in the garage if she had known someone was in there, even though it seems that she did see Toby and Jenna in there. Hanna expresses her desire to come clean to the police and explain it was an accident, but Alison rails on Hanna, basically calling her a fat loser until Aria scolds her, forcing her to apologize. But Alison makes sure she gets her way and makes the girls flee the scene, letting Toby take the fall. Spencer remembers seeing Toby as he was taken away in the cop car to the police station.
In the episode ""The Perfect Storm"", the girls are trapped at school for the SATs while a huge storm hits. When Emily lies to Detective Wilden, she gets a text from A, this causes her to recall a moment she had with Alison. As she flips through the book 'Great Expectations' she sees a letter from herself to Ali. As Emily reads the letter, she remembers the first time she ever kissed Alison and showed her true feelings to her. She is filled with guilt at the sight of the letter for Alison when she realizes that she is the only one left in the library, as she looks for a sign of another person, her bag disappears. Scared and confused, she rejoins the others in the girls' locker room. There, she is called back to the library by Detective Wilden, causing the other girls to follow. Finding the letter, Wilden confronts her about Alison's recently dismantled memorial and forces her to reveal her true feelings towards Alison, right in front of the girls. Just as the girls step up to defend their friend, Spencer's mom, great lawyer that she is, comes in looking for her daughter and tells Wilden that their information is not valid at court and leads them back to the locker room. Leaving Emily to wonder if Alison ever loved her as more than a friend.
In the episode "Can You Hear Me Now?", Aria watches her mother preparing dinner in the kitchen. She suddenly recalls the incident she witnessed, involving her father and Meredith kissing in his car. This time, she additionally remembers how Alison had tried to convince her to tell her mother what she saw. When Byron had tried to call Aria, Alison had warned her not to pick up, correctly suspecting that he would try to talk Aria out of revealing what she saw. Alison had warned Aria that she could risk losing both parents if she didn't tell.