The story of The Sandman begins in 1916, when an ambitious human sorcerer named Roderick Burgess, seeking immortality, holds a grand ritual in his manor attempting to summon the Lord of Death. However, due to a mispronunciation in the incantation, he accidentally traps the Lord of the Dreaming in a specially crafted glass cage. This accidental capture deprives the Lord of his freedom for a century, and his three core artifacts—the sandbag that controls the flow of dreams, the ruby that contains immense power, and the helmet that offers protection—are seized by the Burgess family.
During his imprisonment, the real world descends into chaos without the Dream Lord's regulation: soldiers on European battlefields fall into prolonged slumbers en masse, factory workers suddenly drift into eternal sleep at assembly lines, cases of "sleeping sickness" surge worldwide, while a minority unable to dream grow irritable and violent, pushing social order to the brink of collapse. Though the Burgess father and son guard the cage for generations, they never decipher the artifacts' secrets. The ruby, passed among family members, even triggers several bizarre deaths.
In 1989, as the last heir of the Burgess family dies of old age, the binding spell weakens, allowing the century-imprisoned Lord to finally break free. He returns to the Dreaming, now a desolate ruin—once-majestic palaces lie in tatters, its inhabitants have either vanished or become distorted, and even his loyal raven servant has turned to dust. To rebuild his realm, he embarks on a quest to retrieve the three artifacts: reclaiming the sandbag from a collector in London, he discovers the latter has used it to commit a series of nightmare-induced murders; retrieving the ruby in the Eastern European wilderness, he witnesses an "eternal dream" formed by the gem's uncontrollable energy，trapping hundreds of villagers in slumber for fifty years; the helmet, seized by a hell demon, forces him into a high-stakes intellectual struggle with the Lord of Hell, wagering souls as collateral.
The second volume of Season 2 weaves multiple conflicts. The protagonist ventures to Hell to rescue his former lover Nada, seeking redemption for banishing her there millennia ago after rejecting her affections. However, Hell has undergone a transformation: its former ruler Lucifer abdicates, forcing the key to Hell's dominion upon the protagonist. This key instantly sparks covetousness across the multiverse: the Norse god Odin, accompanied by Thor and Loki, pressures him to cede Hell to Asgard; Titania, Queen of Faerie, besieges the Dreaming with her elven army, claiming Hell as a vassal territory; even Anubis, the Egyptian god of the dead, dispatches envoys proposing a tripartite co-management. Amid threats and inducements, the protagonist ultimately returns Hell to Heaven, a decision triggering a chain reaction—dispossessed hell demons flood the mortal realm, causing a surge in supernatural incidents worldwide.
Concurrently, at the request of his family member Delirium, the protagonist joins her in searching for their long-lost brother Destruction, missing for millennia. Their journey spans time from ancient battlefields to future ruins: discovering Destruction's manuscripts in a medieval monastery, which reveal his perplexity over human warfare; witnessing his dialogue with 19th-century Parisian artists, illuminating his reflections on the symbiosis of creativity and destruction; their ideological clash—Delirium advocating forced return to duty, the protagonist upholding respect for free will—leads to a temporary split. They finally locate Destruction in a post-nuclear wasteland, learning his reason for abandoning duty: witnessing humanity's escalation of violence from the Bronze Age to the Atomic Age, he developed profound doubts about his role as "Destruction," choosing exile to avoid abetting humanity's self-destruction.
The threat of the Furies also permeates Season 2. Lyta Hall, a mortal whose husband died in a supernatural incident, becomes possessed by the Furies out of overwhelming grief, serving as the vessel for "The Kindly Ones." Evolving from unconsciously enacting vengeance, she gains the ability to manipulate others' painful memories: first trapping the scholar indirectly responsible for her husband's death in an eternal dream of remorse, then targeting the protagonist by weaponizing his guilt-ridden memories. Though this threat spans nearly ten episodes, interspersed with seemingly unrelated mortal tragedies as foreshadowing, it culminates in a climactic battle in the Dreaming—Lyta's unleashed pain energy nearly tears the realm asunder, forcing the protagonist to sacrifice himself to restore balance.
The entire story employs a non-linear narrative structure: the seemingly standalone "Doll's House" episode in Season 1 subtly plants clues to Lyta's husband's death; the "ancient pact" mentioned at the start of Season 2 is revealed in the finale as a millennium-old wager between the protagonist and Destiny. Updated from the original 1980s setting to the modern era, the series adds a subplot about social media's impact on dream propagation—a social app accidentally becomes a vector for a nightmare virus, driving a million users to suicidal tendencies in a single day. Despite its deliberate pacing, with episodes often devoting substantial runtime to philosophical debates within dreams, the core narrative traces the protagonist's transformation from rigid traditionalism to sacrificial altruism, concluding with his dissolution and the emergence of a new Dream Lord, bringing this century-spanning mythic epic to a cyclical close.