Season 1

1. Pharmacy

Maine, 1980. Olive Kitteridge is a no-nonsense high school math teacher who doesn't suffer fools and never hesitates to express an opinion, no matter how much hurt she might cause. She treats her husband Henry with indifference and is strict with her son Christopher, who struggles to please her. Henry is the local pharmacist and after his long-time assistant dies from a stroke, he hires a young woman, Denise Thibodeau, whose husband is also named Henry. The two Henrys go hunting with a third man, and the younger Henry is killed in a freak accident. The older Henry grows close to Denise after her husband's death, teaching her how to drive and gifting her an adopted kitten. Olive harbors an attraction to an English teacher at her school and takes an interest in Kevin Coulson, one of her students. Kevin's mother Rachel suffers from bipolar disorder.

2. Incoming Tide

Years have passed and Kevin Coulson, now studying in New York City to be a psychiatrist, returns to town. He struggles with the effects of his mother Rachel's suicide and experiences symptoms of schizophrenia, including vivid hallucinations. Kevin is contemplating suicide himself, but is interrupted by Olive, who engages him in conversation about the town and notices a gun in the back seat of his car. Kevin also saves a former classmate from drowning. Christopher is about to marry, and Olive invites Kevin to attend the rehearsal dinner. Olive dislikes her future daughter-in-law, Suzanne, as well as her prospective in-laws. She invites Kevin to stay with them and to the wedding the next day. On the day of the wedding, Olive acts coldly to those around her, including her new in-laws and members of Suzanne's family.

3. A Different Road

Olive and Henry are saddened when they receive a call from Christopher, now living in California and working as a podiatrist, to say that he and Suzanne are getting a divorce. Christopher appears content with his divorce and explains that he is in therapy. He also tells his parents that he will not be coming to Maine for a visit. Returning home from a dinner out, Olive and Henry stop at a hospital to use the bathroom. Two gun-toting addicts arrive looking for drugs, taking patients and staff members hostage. While held captive, Olive and Henry argue, blaming each other for Christopher's unwillingness to visit. Olive also reveals that she planned to leave him for her former colleague. After the ordeal, Christopher suggests that his parents should enter counseling, but Olive won't hear of it. Henry suffers a stroke and loses his ability to communicate.

4. Security

Olive goes to New York to visit Christopher and meet the family he is building with his new wife, Ann. The visit revives the habits that have kept mother and son apart. Olive criticizes the household and bristles at attempts to understand her. Christopher finally tells her how painful it was to grow up with her anger. She leaves early, still struggling to acknowledge his experience.

Back in Maine, she learns that Henry has died while she was away. The marriage that once frustrated her is now an absence she cannot fill. Her connection with the widowed Jack Kennison offers company, though they initially quarrel rather than comfort each other.

After her dog dies, Olive's isolation becomes a crisis. She goes into the woods intending to end her life, but neighboring children interrupt her. The moment returns the story to the danger glimpsed at the beginning of the series without treating her despair as a settled ending.

A message from Ann tells Olive that she has become a grandmother, even though Christopher has not called her himself. Olive reconnects with Jack. This time, she can begin admitting how her treatment of Henry and Christopher contributed to the distance in her family; Jack also has regrets of his own.

Their final scene offers companionship rather than a complete repair of everything that has happened. Lying beside Jack, Olive finds that she still wants to live in a world she often cannot understand. The series closes with that renewed willingness to stay, while her relationship with Christopher remains something she will have to work on.