Yuri suffers an accident at sea that leaves her unconscious for weeks. Characters wonder if they should just dump her overboard on the assumption that, if she becomes disabled, she wouldn't have a good life, so they should put her out of her misery. They end up not doing this, but this discussion is a very ableist trope.
Mija’s mother died in childbirth before the events of the book. Mention of a pregnant woman dying in the Ring of Fire chapter. A haenyo character allows herself to be swept away by currents for fear of being pregnant while unmarried
The haenyo believe in ghosts, specifically that people whose bodies haven’t been buried properly become “hungry ghosts.” A shaman character is able to speak with them
Some of this narrative takes place during World War II. The chapter “A Golden Rope” has the characters receiving news of the bomb drops on Hiroshima and Nagasaki
There are several news reports of torture, particularly throughout the "Ring of Fire" chapter. The end of the chapter features very graphic descriptions of torture that the protagonist witnesses
The protagonist's son is murdered by a police officer towards the end of the "Ring of Fire" chapter. The officer throws the child against a wall repeatedly.