In Lore, 18-year-old Melora Perseus, better known as Lore, lives a seemingly ordinary life in a New York brownstone with her friend Miles. But as the last of her family, Lore’s life is anything but normal. The descendent of one of five surviving Greek bloodlines, Lore grew up training to fight in the Agon, a competition that takes place every seven years and sees nine Greek gods and goddesses: Aphrodite, Ares, Dionysus, Hephaestus, Poseidon, Artemis, Athena, Hermes and Apollo, turned into mortals and hunted by the Greek houses in the hope that one of their own will kill a god and claim their power. When Lore’s family were brutally murdered at the end of the last Agon, she swore she was done with the tradition. But as the next Agon dawns in contemporary New York City, Lore finds herself forced into the competition as goddess Athena shows up on her doorstep, injured and bleeding. Lore binds her life to the goddess’, swearing to protect her throughout the Agon, in exchange for one thing: revenge. New god Wrath, formally known as Ares, is responsible for killing Lore’s family at the end of the last Agon, and Lore is determined to make him pay.
When Lore returns to Thetis House, home of the Achilleos bloodline where Lore trained as a girl, in order to find out more information about the poem that recounts the creation of the Agon, she is shocked to discover that her childhood friend Castor, who was sick with leukaemia and dying during the last Agon, has claimed the power of the god Apollo, and has thus “ascended”. When Phillip Achilleos attempts to kill Castor, Lore saves his life and, alongside Castor’s cousin Evander, they return to the brownstone, where Castor heals Athena using Apollo’s power. Although resentful of the new god, Athena agrees to an alliance with him for the duration of the Agon. Athena believes that one of the new gods, Wrath, is looking for a poem that will help him both survive the Agon and bring it to the Agon.
In search of the poem, Lore, Athena, Castor and Evander head to a property in Manhattan, which is owned by the Odysseos bloodline. Here, they find the god Wrath torturing members of the Odysseos bloodline, including new god Heartkeeper, who possesses the powers of the goddess Aphrodite. When Wrath kills Heartkeeper, Lore manages to save his mortal daughter, Iro, another of her childhood friends. Iro reveals that the poem Lore and her companions are looking for can be found on the Aegis, the shield worn by Perseus when he slayed the gorgon Medusa, owned by Athena, and now only accessible to Lore as the last of her bloodline.
Lore, Castor, Miles and Athena then go to The Frick Museum, after Miles recognises it in the background of a photo of Reveler, another new god who possesses the powers of the god Dionysus. Upon arriving, they find evidence of another slaughter, but Miles’ hunch has proven correct and they also find Reveler. Before they can convince him to join their alliance though, Hunters arrive and injure him. Athena then kills him out of mercy. Before he dies, however, Reveler reveals that Lore’s deceased landlord, boss and friend, Gil, was actually the god Hermes, and has since actually been killed by Wrath at the beginning of the Agon.
Upon leaving The Frick, Lore runs into Belen, the mortal son of Wrath and one of her childhood tormentors. She chases him and cuts off his thumbs, so that he will no longer be able to hunt in the Agon, thus bringing shame to both him and his family. A drone, operated by one of Wrath’s Hunters, drops a bomb on Fifth Avenue. Castor saves Lore from being injured or killed in the blast and Athena holds a stone façade, preventing it from falling on those helping the victims of the blast.
After recovering from the blast, the group is lured to Morningside Park by Artemis, who injured Athena at the beginning of the Agon. Here, Artemis uses her powers over wild animals to attack the group. Artemis then falls to her own death. Iro shows up with reinforcements and kills Castor. Full of rage, Lore does not notice when Castor comes back to life and tells Iro to leave before Lore can kill her. Suddenly, a flood begins.
As New York City becomes inundated with water, Lore and her friends know that it isn’t the result of any natural event, but rather the work of a god – of Tidebringer, Poseidon reborn. Lore and Athena descend into the sewers to find Tidebringer imprisoned at River House, a property owned by the Kadmou bloodline. They find Tidebringer and she reveals that it was not Wrath who killed Lore’s family, but rather Athena herself. This is because, during the last Agon, Lore snuck out and stole the Aegis. Athena sought to find it and tortured and killed Lore’s family in order to do so. Lore stabs herself, hoping that in doing so she will also kill Athena, whose life is bound to hers, but Athena reveals she did not, in fact, bind her life to Lore’s. Athena attacks Lore and flees. Lore, guided by a vision of Gil/Hermes, makes her way through the sewers, eventually passing out. Castor finds her and heals her, before leading her from the sewers back to her friends.
Lore retrieves the Aegis where she hid it at the end of the last Agon. She and her friends discover that Athena has allied with Wrath and the two plan to end the Agon by making a sacrifice to Zeus by killing all the humans in New York. The flood has functioned as a way to force people to evacuation points, such as Grand Central Station, where Athena and Wrath will kill them. Lore pleads with Athena, who eventually turns on Wrath when Lore willingly gives her the Aegis, killing him. She then forces Lore to stab her, thus willingly giving her own power to Lore and dying. Lore uses her new powers to stop the deaths of those at the evacuation points.
The plan foiled, Lore and her friends return to the brownstone, where Lore and Castor admit their feelings for one another, knowing that when midnight strikes, the Agon will be over and both of them, now in possession of gods’ powers, will lose their mortal forms until the next Agon. Castor realises that the god Apollo must have willingly given his powers to him, a dying twelve-year old, much like Athena gave her powers to Lore, and that this is why Castor was still immortal and unable to be killed by Iro. As midnight draws closer, Lore pleads with Zeus to let the Agon end, to let her and Castor remain mortal. She closes her eyes and when she opens them, both she and Castor are still mortals, still on the roof of Lore’s brownstone. “As the eighth day began, Lore smiled and kissed him”.