Young-sook meets Mi-ja as a child after catching her stealing food from the Kim family garden.

Young-sook and Mi-ja make their debut together as baby divers on Jeju Island.

Young-sook's mother drowns after her wrist strap becomes trapped in an abalone shell while diving.

Young-sook and Mi-ja travel to Vladivostok for seasonal diving work and talk of marriage on their sleeping mats.

Young-sook meets the charming Sang-mun at the Jeju dock when the girls return from Russia.

Young-sook's grandmother announces arranged marriages for both Young-sook and Mi-ja without revealing the grooms' identities.

Young-sook and Mi-ja both give birth to their first children during a Vladivostok diving expedition.

Japan surrenders and American forces replace the Japanese as the new colonizers of Jeju Island.

Jun-bu returns from university, Young-sook goes back to diving, and she soon gives birth to a son.

A pro-democracy demonstration in Bukchon erupts into a riot; protesters are shot and many are arrested.

Soldiers round up all Bukchon villagers in the local school after two of their men are found dead.

Mi-ja escapes with her husband while Jun-bu, Young-sook's son Sung-soo, and Yu-ri are killed in the massacre.

Young-sook returns to Hado and finds Mi-ja living there; she refuses her friend's every attempt at reconciliation.

Young-sook is nominated and voted in as the new leader of the local diving collective.

Young-sook hears Mi-ja's full recorded explanation, forgives her old friend, and invites Mi-ja's descendants to swim.

Young-sook and Mi-ja form a deep bond as childhood friends and fellow baby divers on Jeju Island, growing together through their training, arranged marriages, and first pregnancies. Post-war political chaos fractures their island, and the violence culminates in the Bukchon Massacre, where Mi-ja escapes with her husband and leaves Young-sook's family to be slaughtered. Young-sook carries this grief and fury for decades, refusing all of Mi-ja's attempts to explain or reconcile. Her anger shapes every major decision of her later life, costing her connection to her own daughter when the younger generation bridges the families' divide. Decades later, when Korea finally erects a memorial to the massacre victims, Young-sook is given one last chance to hear her friend's side of the story. Understanding Mi-ja's hidden suffering, she at last releases her rage and invites Mi-ja's descendants into the ocean as a gesture of peace.

The headline story of Young-sook and Mi-ja's friendship, fracture, and forgiveness.

Young-sook's mother defends Mi-ja to the skeptical diving collective and allows her to join the group.

An island-wide anti-Japanese demonstration turns violent; soldiers later raid the family garden and beat Young-sook's mother and Mi-ja.

Yu-ri is grabbed by an octopus during a dive and nearly drowns; she later wakes up permanently brain-damaged.

Mi-ja shares her book of charcoal rubbings with Young-sook on their first dive day as a gesture of friendship.

Russian sailors buy ice cream for the girls in Vladivostok; Mi-ja declares she and Young-sook must always stay together.

Young-sook returns home from Russia to learn her youngest brother has died and other brothers were conscripted.

Jun-bu arrives on the Jeju ferry; his mother Do-saeng negotiates the marriage arrangement with Young-sook's grandmother.

Mi-ja visits Young-sook's village to pray to a fertility goddess before her husband leaves on a long business trip.

Young-sook visits Mi-ja in Jeju City and finds her frightened because Sang-mun has been missing in the north.

Mi-ja arrives at Young-sook's home looking gaunt after losing a baby and admits that Sang-mun beats her.

Jeju Island is placed under martial law and movement is restricted under a deadly ring-of-fire coastal order.

Young-sook gives birth to a daughter named Joon-lee in the painful aftermath of the Bukchon Massacre.

Young-sook confronts Mi-ja at a massacre anniversary memorial; Mi-ja retaliates by blaming Young-sook for past tragedies.

Wan-soon vanishes during a dive and is never found; grieving dive chief Gu-ja resigns her leadership role.

Young-sook opens Mi-ja's old letters on the beach and discovers their shared charcoal rubbings tucked inside.

Behind the headline events of the novel lies a rich texture of smaller but essential moments that define who Young-sook and Mi-ja are. From Young-sook's mother taking in a hungry orphan girl to the shared rituals of diving culture, the friendship between the two women is built from dozens of quiet gestures and acts of loyalty. Danger and loss shadow them throughout, from Yu-ri's brain-damaging accident to the drowning of the young diver Wan-soon years later. As Korea's political violence closes in, the women's private lives grow increasingly strained — Mi-ja suffers in an abusive marriage while Young-sook fights to protect her children under a corrupt regime. After the massacre, both women carry wounds they cannot name to each other, and the village itself splits into rival factions around their feud. The truth about their broken friendship only begins to surface when Young-sook finally opens the letters she has refused to read for decades.

The supporting moments that shaped two women's lives and deepened their bond.

Do-saeng is elected new diving chief after Young-sook's mother's death; Young-sook must now lead her family alone.

Mi-ja is betrothed to Sang-mun against her wishes while Young-sook learns that Jun-bu will be her husband.

Young-sook and Mi-ja unexpectedly find themselves on the same expedition and discover they are both pregnant.

Young-sook gives birth to a son named Sung-soo, providing the male heir her household needs for ancestor worship.

Young-sook tells Jun-bu she must return to the sea; he agrees and supports her return to haenyeo work.

Sang-mun escapes from North Korea and arrives gaunt and sickly at the village's annual harvest festival.

The Northwest Young Men's Association arrives on Jeju and begins killing innocent islanders accused of communist ties.

Rebels seize the Bukchon police station and destroy roads; the government launches house-to-house searches for communist sympathizers.

Young-sook implores Mi-ja to save her three children; Mi-ja says she will take only one and only if Sang-mun agrees.

War breaks out on the Korean peninsula; Young-sook witnesses bodies being dumped into the surrounding ocean daily.

Do-saeng presents Young-sook with a prized glass diving mask after the collective's vote for chief goes to Gu-ja.

Scientists arrive to study haenyeo cold tolerance; young Joon-lee enthusiastically serves as their intermediary with the divers.

Joon-lee arrives home from university riding behind Yo-chan on a motorcycle and announces they plan to marry.

Mi-ja reveals she arranged Joon-lee's removal from the guilt-by-association records; Young-sook still refuses to forgive her.

Clara plays Young-sook a recording in which Mi-ja reveals that Sang-mun raped her the day they first met at the dock.

Beneath the sweep of history lie the pivotal moments of choice and revelation that determine the fates of Young-sook, Mi-ja, and everyone they love. From the quiet decision of a grandmother to marry off two young women into vastly different lives, to the moment a desperate plea at a massacre site goes unanswered, this pool tracks the hinges on which the story turns. Many of these moments are only fully understood in hindsight: Mi-ja's marriage to an abusive man, her refusal to save Young-sook's children, and her secret act of protecting Joon-lee all make a different kind of sense once the truth is known. The arrival of scientists, a wedding announcement, and an unexpected revelation on an iPhone all signal the slow thaw of decades of frozen grief. The final revelation — that Sang-mun raped Mi-ja the day the two friends first met him — reframes the entire story and makes forgiveness at last possible.