Joel feels an inexplicable urge to skip work and take a train to Montauk, where he encounters Clementine.

• Joel wakes up feeling sad on Valentine's Day, noticing other couples' celebrations but feeling solitary as he begins his usual workday.
• Heading to the train station, he feels strangely drawn to an ad for a train to Montauk, and impulsively decides to go there.
• On the desolate Montauk beach, Joel spots a woman with blue hair and an orange jacket, wishing to meet someone new but his shyness keeps him at a distance.

Joel and Clementine meet on the Montauk beach and later connect on the train ride back, leading to an exchange of personal insights.

• Joel encounters the blue-haired woman, Clementine, at a local restaurant and observes her from a distance, sketching her in his notebook.
• They meet again on the train back, and Clementine breaks the silence, introducing herself and striking up a conversation about whether they have met before.
• Clementine's frequent hair color changes are mentioned, which will be significant in their conversation and the overall narrative of the film.

Clementine and Joel discuss their differences in temperament, with Clementine being impulsive and Joel being reserved.

• Clementine reveals her quick temper changes and Joel, more reserved and less expressive, struggles to keep up with her pace.
• They talk about the meaning of the name 'Clementine', and she ironically states that she is more vengeful than merciful.
• Clementine apologizes for being rude earlier that day, and Joel, a bit confused, simply nods in response.

Joel and Clementine's day together leads to an unexpected connection, but Joel's hesitance causes him to part ways with her for the evening.

• Clementine takes an interest in Joel's kindness, although she's not sure if she will like it in the future, she likes that he is kind at the moment.
• After offering her a ride in his car, Joel is invited into Clementine's house for a drink, where they share more about themselves.
• Clementine, getting close to Joel, suggests a date at the Charles River, but Joel, feeling overwhelmed, declines and leaves after getting her phone number.

The narrative reveals that Joel and Clementine were once in a relationship, which they have both erased from their memories.

• Joel and Clementine, who appear to be strangers, actually have a past together as a couple, which neither of them remembers.
• Before the events of their meeting in Montauk, Joel is heartbroken over his breakup with Clementine and discovers she has erased him from her memory.

Struggling with the loss of Clementine, Joel decides to undergo the same memory erasure procedure she did.

• After learning Clementine has erased her memories of him, Joel decides to undergo the same procedure at Lacuna Inc.
• Dr. Howard Mierzwiak explains the procedure to Joel, requiring him to gather items related to Clementine and record a testimony about her.

The technical process of erasing Joel's memories of Clementine is initiated as he falls into a deep sleep.

• Joel records his memories of Clementine, detailing how they met at a beach party in Montauk.
• The technicians of Lacuna Inc., Stan and Patrick, arrive at Joel's house to begin the memory erasure as he sleeps.

Joel experiences his memories with Clementine being erased, starting with the most recent and painful ones.

• Joel awakens in the labyrinth of his mind, reliving his memories with Clementine as they are being erased.
• He experiences their last argument, filled with hurt and anger, and Clementine leaves, stating that she is erasing him from her memory.

Joel desperately tries to hide Clementine within his memories to prevent them from being erased.

• As the erasure continues, Joel regrets his decision and tries to hide Clementine in memories where she doesn't belong.
• They hide in a childhood memory of Joel's, which temporarily halts the erasure, but Dr. Howard intervenes and resumes the process.

The technicians overseeing Joel's memory erasure exhibit unprofessional behavior, neglecting their duties.

• Technicians Patrick and Stan show a lack of professionalism by drinking and neglecting their monitoring duties.
• Patrick reveals he has stolen panties from a previous patient and is now dating her, which disgusts Stan.

Joel relives memories of passion and deep connection with Clementine, becoming increasingly desperate to stop the erasure.

• Joel relives intimate and joyful memories with Clementine, showcasing their strong emotional connection.
• Despite his efforts to stop the erasure, the memories continue to fade away, including moments of shared laughter and days at Montauk.

While Joel's memories are being erased, unprofessionalism and personal drama unfold among the Lacuna staff.

• Technicians Stan and Mary engage in unprofessional behavior, drinking and dancing on Joel's bed while he is unconscious.
• Dr. Howard is caught in a compromising situation with Mary by his wife, leading to personal revelations and Mary's decision to quit.

Joel relives his earliest memories with Clementine, leading to an epiphany about the value of their shared experiences.

• Joel revisits his first memory of Clementine, reflecting on their initial connection and her candid warning about relationships.
• Realizing the importance of their experiences together, Joel wishes for a chance to start anew with Clementine.

Joel and Clementine's memories have been erased, but they cross paths again due to the impulsiveness that initially brought them together.

• The memory erasure procedure concludes, and Joel wakes up having forgotten Clementine completely.
• Mary, disillusioned, sends out the patients' testimonial tapes, leading to Joel and Clementine's rediscovery of their erased relationship.

Joel and Clementine confront the harsh truths about their past relationship but decide to give their love another chance.

• Clementine listens to her tape revealing her harsh opinions of Joel, leading to a confrontation and moment of doubt.
• Despite the painful truths, Joel and Clementine decide to embrace their imperfections and attempt to renew their relationship.