Pretty Little Liars: the story of one friendship group that goes through hell after one group member is declared dead.

Season 1 is constantly fleshing out via flashbacks and present-day discussions the relationship that each liar had with Alison, as well as their relationship with Alison as a group leader. Aria was close with Ali as they had a fair bit in common; fashion, literature and boys, but Ali needed to remain the more knowledgeable and powerful in those areas. Emily loved Alison as more than a friend but Emily always got mixed signals from Alison - sometimes the kisses were for practice, while other times they felt very genuine. Hanna loved and needed Alison's warmth she provided in difficult moments such as binge eating, however, Alison frequently dropped insensitive one liners that hurt Hanna. Alison saw Spencer as her rival, as Alison seemingly always wanted what Spencer had but would never admit it. As a result, Alison's jealousy lead her to threaten Spencer to end the good things in her life. Spencer frequently built up the courage to speak up on behalf of the group, but this only fuelled Alison's rivalry with Spencer, as opposed to end the competitiveness. Overall, each Liar had a solid individual relationship with Alison however she constantly put them down. This conflict is heavily explored throughout the entire season 1.

At the end of Alison's funeral in the pilot, Spencer, Aria, Hanna and Emily receive a text which reads "The bitch is dead and it'll all be your fault. I'm just getting started with you four. -A"

The majority of the first season of the show is dedicated to A establishing themselves as a real and dangerous threat to the girls. In every episode, each liar receives a new threat: do as A says, or else their secret is exposed. By the end of each episode, each liar either successfully did as A said and therefore avoided their secret being exposed, or, failed to do as A said and therefore A exposed the secret themselves. (The latter leads to domino effects in the next episode.) In this way, and with only 15 episodes, each season 1 episode is action packed with secrets and lies. Essentially, season 1 is a season of blackmails.

Some of the secrets that A will threaten to expose throughout the season include:

- Aria is in a relationship with her teacher.
- Hanna has shoplifted thousands of dollars worth of expensive items.
- Emily is questioning her sexuality and kissed a girl (Maya) at a party.
- Wren and Ian (Melissa's boyfriends) kissed Spencer.
- Spencer is taking drugs to keep her up all night, so that she can study longer, to boost her performance at school.
- Emily loved Alison as more than a friend.
- Aria knows that her father cheated on her mother but she has been keeping this a secret from her mother because her father offered to pay for college.
- Hanna's mother killed Mrs Potter (an old rich lady, the last in her family) by drugging her water, and she has been taking increments of money from Mrs Potter's bank account to pay off the home mortgage.
- The girls were with Alison when she threw a firework in Jenna's garage and blinded her. Therefore, the girls know Toby never blinded Jenna, like Alison declared.

Some examples of what the girls must do in order to prevent the above secrets being exposed:

- Hanna must stop her dad from marrying Isabel whilst they are saying their vows at the wedding.

- Hanna must get Kate (Isabel's daughter) expelled from Rosewood High.

- Spencer must tell her parents that Melissa paid someone to write her thesis and therefore Melissa does not deserve the praise they shower her with (A provides the proof of this).

- Emily must give Ella a ticket to the movie that Aria and Ezra will be seeing on Saturday night on their date.

- Hanna must eat 8 large cupcakes in the school cafeteria, inducing a relapse in her eating disorder.

- Emily must tell her dad that she wishes he would stay gone fighting in the army, rather than be home.

- Hanna must shoplift again, or else A will tell the police of all her prior shoplifting incidents. This is a painful cycle: keep doing wrong, to avoid that wrong being exposed.

These threats from A are small and trivial in comparison to A's bigger picture: simultaneously to their individual threats, A is framing them for Alison's murder, as promised in A's first text at Ali's funeral. A does this by anonymously giving Detective Wilden convincing evidence of the girls having killed Ali. The Liars are aware that A is doing this, and A uses this as another form of bribery to do as A says. These anonymous tips make Wilden so sure that the girls killed Ali, and so he is building a case against the Liars all throughout season 1. However, the tips are not strong enough to lead to a formal arrest, rather A's tips merely increase Wilden's suspicion. Some of the evidence A will throw around that suggests the liars collectively wanted Ali dead include:

- a recording off Alison's phone whereby Spencer declares to Alison that "what's a leader without any followers? The question isn't whether we would exist without you, but whether you would exist without us. Because as far as I can tell Ali, you're dead to us already.

- a scrapbook that Emily made of Ali: the first few pages include happy photos of Ali and Emily with love heart decorations. The final few pages have pictures of Ali with devil horns and skulls drawn in, with captions "she loves me, she loves me not".

- CCTV proof of Aria destroying Alison's memorial - Aria did this due to pure anger after A gave Aria proof of Ali lightly sexting her father, Byron. (Byron never reciprocated.

- a voicemail Hanna left for Ali: "Ali, pick up. You can't keep avoiding me. I swear to god if you tell one more person what you saw me doing I will kill you, this isn't funny anymore." Unlucky for Hanna, her exaggeration can now be interpreted literally, given Ali is dead. (This voicemail is in reference to Hanna eating and intentionally throwing it up. Hanna struggles with relapses in her eating disorder.)

Importantly, one way the Liars fight back against the accusations that they killed Ali, is by shifting the blame to Ian Thomas, Melissa's fiancé. At school one day, the Liars shockingly find Ali's diary lying on the floor in the middle of the school hallway. The Liars argue over how it got there and who will keep it. Eventually, Emily takes it home and she only read as far as the pages where Ali shockingly wrote about a relationship she had with Ian. Ali told one unnamed friend about her sexual relationship with Ian. This infuriated Ian as he feared he will be imprisoned as a pedophile if Rosewood found out about this relationship. The Liars claimed that this was a motive for Ian to have killed Ali, so to clear their own name, the girls rip out these pages from Ali's diary and turn them in to the Rosewood Police. In a plot twist, we learn that the Liars' friend, Officer Garret Reynolds, is actually best mates with Ian, and Garret therefore destroys these pages as opposed to filing them as evidence. Of course, being new to these games, the Liars did not make copies and the next day at school, Emily realises that Ali's diary has been taken out of her bag. "Nice try! I'm everywhere, bitches. -A"

The fatal season 1 finale is all about the liars coming to sense with the monsters they have become. Throughout season 1, they were always willing to throw other people under the bus and lie to those they love in order to protect their own secrets - this is a moment of realisation as to why the show is called Pretty Little Liars. In the season 1 finale, the Liars agree that it is time to change their ways; rather than devoting all their efforts to doing as A says, they decide to devote their efforts to actually finding out who A is and ending this madness.

The season 1 finale commences with Spencer's threat-of-the-episode: "Oh Spence. Always wanting your sister's boyfriends. Tell Melissa about your summer fling with Ian, or I will. Tonight." Attached is a picture of when Ian kissed Spencer while he was training her in hockey which confirms that A's threat is most definitely real. When Hanna asks how A could possibly have such a picture, Spencer asks Hanna "are you seriously still asking how? A knows everything. That's the rule." Either way, Spencer will lose, as A has declared that her secret must come out one way or another. Spencer states that she would rather Melissa find out directly from her, rather than via an anonymous email. The Liars decide to stay true to their prior words; to use this situation to catch A in the act as opposed to blindly doing as A says.

Spencer lays in her bed starring at the ceiling and she has a conversation with herself in her head. She is aware that if she were to tell Melissa about her and Ian, A will somehow be watching or listening, to ensure the job is being done. Spencer tells herself to "think, think, think" of a place that is so physically small that A will be forced to come close to hear and see what is going on. Spencer visualises herself wrestling A and pulling off the hoodie and then she sits up in her bed as she has a lightbulb moment: "the bell tower," she says to herself.

Melissa gets in Spencer's car and sincerely thanks her for taking her out for dinner for some much-needed sister bonding, especially after Spencer's "immature" murder accusations towards her fiancé. Melissa points out to Spencer that she missed the turn onto the highway towards the restaurant, to which Spencer replies they are taking a scenic detour. After Spencer dodges numerous questions about the detour, they finally make it to the church; that place in Spencer's dream that is so small that A won't be able to run from when A is eavesdropping. "I know you're confused Melissa. You said I've been acting weird the past couple weeks. Tonight is going to be another weird night but I promise you, if you just do as we say, everything will go back to normal and I can stop being weird. We promise." Melissa asks who "we" is, but she answers her own question when she walks into the church with Spencer and sees Hanna, Aria and Emily already inside crouching behind the church pews. Hanna, Aria and Emily tell Melissa that she needs to stay here with them, hidden, while Spencer goes upstairs to the bell tower to "end the craziness". Melissa complies out of laziness and utter confusion as she doesn't even know which question to ask first. Spencer walks to the top of the church and into the bell tower, knowing that A will eventually show up to see if Spencer is completing her task. At the top, Spencer smiles, as this area is so isolated and so small; perfect for luring A.

From their hiding positions crawling on the ground, Aria, Hanna, Emily and Melissa hear the front door of the church open. Scared to stick their heads up from the ground, they can only see black boots walking into the church. Thinking they've successfully lured A into a small and inescapable area, they stay quiet and let this person walk upstairs to Spencer. Spencer hears footsteps coming up the stairs and she smiles again at the thought of being so close to A.

Knowing Melissa is safe downstairs with her friends, Spencer plays dumb for A. "Melissa, is that you? Thanks for meeting me here. I need to tell you something." The black boots that the girls saw enter the church downstairs step out of the shadows and the camera pans up not to reveal A, but instead, Ian Thomas. "Hello Spencer," says Ian. Spencer gasps and mutters "what the hell?". Downstairs, Aria is seen mouthing to her friends "I can't hear anything." Hanna gives 3 fingers, reminding her friends that the plan was to wait 3 minutes before rushing to Spencer's aid. All the while, Melissa is still confused as to why she is here.

Ian begins to talk. "You're making another mistake tonight, Spencer". Spencer tells Ian that she has no idea what he's talking about. "For a girl who prides herself on being an A+ student, you sure are one dumb bitch." Spencer looks at Ian with disgust, having never seen this side to him before. Even when she blamed him for killing Ali, Ian always stayed relatively calm. Tonight, something is wrong. "Waiting on Melissa are you? To tell her about our little mistake last summer? Why? What good would that do?" asks Ian, probably rhetorically. And it clicks to Spencer: A was one step ahead, and anonymously informed Ian of Spencer's task. Ian continues: "You're sick, Spencer. Your sick mind can't let your sister and I be happy. If you're not destroying her reputation, you're plotting ways to destroy mine. Lucky me, I'm the one who got the murder accusations." Ian takes a step closer. Spencer tells Ian that he is scaring her and that he needs to calm down. "You're beyond repair, Spence. You're out of control."

Ian quickly steps towards Spencer and grabs her by the throat, choking her, and lifts her up against the window of the bell tower. "Wilden is right. You killed Ali. And tonight your regretful heart reached boiling point. So you took your own life. How's that story? I'd believe it." (A quick flash suddenly goes off, almost as if someone took a picture.) Before Ian can throw Spencer off the bell tower, a black hoodie suddenly emerges from the immediate shadows and hits Ian with a shovel across the head, bashing his skull, causing him to drop Spencer back onto the ground. While Spencer catches her breath after being chocked, the black hoodie throws Ian's body out the window off the bell tower. This loud thump causes Aria, Emily, Hanna and Melissa to jump up. They sense something went wrong and so they open the church door and all scream at the sight of Ian's dead, bloody body in front of them. As Melissa runs to her fiancés' dead body uncontrollably crying, Aria looks up and sees A jumping out the window from the top of the bell tower, sliding down a pole. On the ground, A begins sprinting away to save their identity. Aria and Hanna start chasing after A but they don't get far before they realise Emily is not following them. Aria and Hanna see Emily at the top of the bell tower window waving them over. At the top, Emily, Aria and Hanna find a shaken Spencer sitting in the corner holding the shovel with Ian's blood, repeatedly mouthing "I didn't kill him." The Liars assure Spencer that they believe her, and they all hug her out of gratitude that she's still alive.

Aria suggests to the group that if they don't get out of here right now before someone calls the cops, the cops may think they killed Ian. Spencer sees Melissa screaming over Ian's dead body, and she convinces her friends that leaving is not appropriate. As Spencer goes to comfort Melissa, Melissa violently pushes Spencer to the ground and spits on her. "Go to hell! The four of you!" declares Melissa.

All four Liars' phones vibrate at the same time and they read it aloud while Melissa continues to cry: "I couldn't let Ian take one of my dolls. That would ruin my fun! -A". The screen smashes to black, ending season 1. The Liars' plan to catch A lead to a dead Ian.