Sentenced to 15 months for a crime she committed 10 years earlier, Piper Chapman leaves her supportive fiancé Larry for her new home: Litchfield Penitentiary, a women's prison. Her counselor, Sam Healy, empathizes with her and gently gives her tips to survive. Piper grapples with the racial dynamics of prison life and learns some of the rules. She befriends some of the inmates, including Nicky Nichols, a recovering heroin addict. Piper later offends Red, the powerful matriarch of the prison kitchen, who responds by serving Piper a bloody tampon. Piper is then shocked to discover that Alex Vause, her former lover who recruited her into carrying drug money, is in the same prison. Meanwhile, new inmate Daya Diaz is greeted by her mother Aleida, who is also incarcerated, with a slap to the face.

After insulting Red's food, Piper is starved out by the kitchen staff. She struggles to offer up an acceptable apology to Red. Alex tries to give Piper a piece of cornbread, but Piper rejects it. With help from fellow inmate, Suzanne "Crazy Eyes" Warren, Piper manages to prepare a medicated lotion for Red's back problems; Red appreciates the effort and stops starving Piper. Suzanne later makes a romantic move on Piper. Meanwhile, the kitchen freezer is irreparably damaged, and Red manipulates Healy into buying a new one. Daya forms a secret friendship with Bennett, a friendly correctional officer.

Piper's best friend Polly takes more authority over their soap-making business. Piper deals with romantic advances from Suzanne. After Suzanne submits a request to bunk with Piper, Piper firmly rejects Suzanne's advances. Transgender inmate Sophia Burset has her dose of exogenous estrogen reduced in response to budget cuts. Sophia asks her wife, Crystal, to smuggle pills into the prison; Crystal flatly refuses, asking her "How fucking selfish can you be?" Piper moves into the cube of Miss Claudette, a stern inmate with high expectations for cleanliness and privacy. Miss Claudette's code of conduct is violated when Suzanne vengefully urinates on the floor of their space.

Healy assigns Piper a work assignment at the electrical shop. After Piper loses a screwdriver, the prison staff searches high and low to find it before it is used as a weapon. A skeezy correctional officer, George Mendez, molests Piper during the search. When Piper returns to her cube with the screwdriver, it places more strain on her relationship with Claudette. Meanwhile, Tricia Miller schemes to prevent her girlfriend Mercy's release by planting drugs in her bunk, but Claudette convinces Tricia not to ruin Mercy's chance for freedom. Healy informs Claudette that there is interest in reopening her case, but she declines. Upon receiving a letter from her old friend Baptiste, Claudette ultimately agrees to have her case reopened.

While relaxing in the exercise yard, Piper sees a chicken. When she mentions it in passing, Red recounts her dream of cooking a proper chicken and offers a gift to the person who catches the chicken. Larry discovers that Alex gave Piper's name to the feds. To keep Piper focused on life beyond prison, Larry lies to her. Polly arranges for Piper to take a business call, but Piper skips it to chase the chicken. Lorna Morello ends her sexual relationship with Nicky. Sophia asks Sister Ingalls for estrogen pills, but Sister Ingalls refuses. At the chapel, the overloaded ceiling collapses from a heavy cross that Pennsatucky had tried to hang. The prisoners work to clean up and repair the damage. Miss Claudette starts researching her legal appeal. Bennett and Daya pass notes to each other; Aleida advises her daughter to date another guard who can do her favors.

Piper starts to view Alex fondly, now believing that she didn't name her. Larry agrees to write an article about Piper's term in prison. Healy is tired of dealing with the inmate's problems and announces elections for the women's advisory council. Red encourages Morello to run for WAC; this upsets Nicky, as she believed that she was Red's second-in-command. Healy encourages Piper to run for WAC, but when she refuses, Healy places her on the council anyway. The guards start searching for a missing mobile phone; Piper finds it hidden in the wall of the bathroom. The increased contraband searches threatens Mendez's drug operation. A friendly CO, Susan Fischer, gets assigned to Litchfield. Daya performs oral sex on Bennett for the first time, during which she discovers that he has a prosthetic leg.

Janae Watson is released from the SHU after arguing with the guards during the screwdriver incident. Janae concludes that it was Piper who misplaced the screwdriver; Piper confesses, but points out that Janae was initially sent to the SHU for arguing with the guards. Piper tries to make nice with Alex. Taystee anticipates her upcoming disciplinary board hearing. Mendez pressures Red into smuggling drugs into the prison, but she refuses. Pennsatucky, who was hoping to use the WAC election to obtain false teeth, is infuriated by Piper's appointment to WAC. Piper hands Healy the missing phone in exchange for getting the prison's running track reopened. When Healy does not go through with the plan, Piper manipulates Fischer into reopening the running track, which pleases Janae.

The flu bug circulates through the prison. Larry's article is printed. While Piper is happy about the article, she is upset that most of the information is inaccurate. Healy reads the article and begins acting coldly towards Piper upon discovering her history with Alex. Piper and Alex flirt and reminisce while they try to fix a dryer. Pennsatucky locks Alex into the dryer as revenge. Polly gives birth. When Tricia goes into drug withdrawal, Caputo orders Mendez to investigate how the drugs entered the prison. Over Nicky's objection, Red cuts off Tricia, who is subsequently sent to SHU. Angry at Red for cutting off Tricia, Nicky informs Mendez that Red uses Neptune's Produce, a vendor affiliated with the Russian bosses from Red's background, to smuggle contraband into the prison. Taystee is granted parole. Daya discovers that she is pregnant, and Bennett is the father.

Mendez uses Red's smuggling connections to move drugs into the prison. When Red flushes them down the toilet, Mendez issues Red a death threat and urinates into the Thanksgiving gravy. Pennsatucky and Alex clash over their views on homosexuality and religion. During Taystee's release party, Piper and Alex share a sexually charged dance; Pennsatucky snitches on them for "lesbianing together," after which Healy sends Chapman to SHU. Piper is enraged that Healy is punishing her, and she struggles to deal with the isolation. Larry meets Maury Kind, an NPR personality. Crystal informs Sophia that she has become romantically interested in her pastor. With Sister Ingalls's encouragement, Sophia gives Crystal her blessing. Daya agrees to keep her baby. Taystee gets released but finds that her support network is missing. Caputo orders Healy to release Piper from SHU when it becomes clear that her transfer was unjustified. Healy calls Larry, informing him about Piper and Alex's sexual relationship. Upon returning to camp, Piper has sex with Alex.

Piper is unable to contact Larry, though she finds out from her brother Cal that Larry had landed an NPR radio interview. Bennett learns of Daya's pregnancy and is concerned that the system will discover their relationship, which could result in disciplinary action for both. A scared straight program arrives at the prison; the inmates attempt to intimidate the visiting juvenile delinquents, but they have difficulty intimidating Dina, a young paraplegic "gangster". Piper succeeds by telling Dina the scariest part of prison is coming face-to-face with who you really are. Pennsatucky starts a faith healing crusade that quickly ends when she forcefully removes Dina from her wheelchair; Pennsatucky had been tricked by Piper into "healing" Dina. Miss Claudette reunites with Baptiste. Tricia returns from the SHU and struggles to make amends with Red. Mendez manipulates Tricia into selling his drugs. Upon clocking Tricia's state, Mendez locks her in a closet to prevent her from revealing the drugs. When he returns, Mendez discovers Tricia had taken all the drugs, overdosed, and died. He manipulates the scene to make it look as if Tricia had hung herself. Nicky and Red blame themselves for Tricia's death and they both resolve to bring Mendez down.

While the prison officials cover up Tricia's death, the inmates organize an informal memorial for her. Tricia's death affects Mendez, and he vents over drinks with Bennett. Aleida, Daya and Red scheme to cover up Daya's pregnancy; Daya will have sex with Mendez, which will then deflect suspicions once her pregnancy becomes apparent. During their encounter, however, Mendez uses a condom. After Piper learns that psych is worse than SHU, she successfully petitions Caputo to have Pennsatucky returned to general population. Piper's bravery brings Alex closer to her. Miss Claudette and Baptiste anticipate her potential release. Piper and several other inmates listen to Larry's NPR interview; Larry's comments are hurtful towards Suzanne and Miss Claudette, and his comments regarding fidelity convinces Piper that he knows about her relationship with Alex. Piper finally contacts Larry and confesses her infidelity. Larry reveals that Healy had told him that she was put in the SHU for "lesbian activity." Piper admits that she loves Alex, which Larry sees as a deep betrayal; Larry then tells Piper that Alex did name her, thereby admitting that he lied earlier, and tells Piper than he needs time away from her.

Caputo catches Mendez having sex with Daya. To avoid a rape investigation, Mendez is put on unpaid leave. Daya tells Bennett about her plot, though he is displeased about the framing. Mendez tells Bennett about Red's smuggling operation; Bennett informs Caputo. Piper makes up with Miss Claudette, who is hopeful for the results of her hearing; however, her appeal is denied. Returning to camp, Claudette angrily chokes CO Fischer, which results in her being sent to maximum security. Unable to adjust to life outside, Taystee purposely commits a crime to return to the prison. A journalist following Larry's interview asks Natalie Figueroa, the deputy warden, about spending cuts at Litchfield, despite an increase in the prison's funding. Alex admits she ratted on Piper for dumping her, but she had lied in order to rekindle their relationship. Larry asks Piper to marry him immediately. Pennsatucky is encouraged by her lawyer to "witness" to Piper. Following Pennsatucky's instructions, Piper "prays" for forgiveness, but she refuses to be baptized. Pennsatucky sees this refusal as another instance of being "disrespected" and announces her plans to murder Piper.