The following version of this book was used for the creation of this study guide: Lynch, Paul. Grace: A Novel. Little, Brown and Company, 2017. First Edition.

The novel opens as Grace Coyle, a 16-year-old girl, is dragged out of bed one morning by her mother, who brings her outside and cuts off her hair. Her mother then tells her, "You are the strong one now" (5). At dinner that night, Grace's mother tells her that she must leave home disguised as a boy to find a way to make money for their family. It is the first year of the Great Famine in Ireland, and Grace's single mother cannot get enough food for the family on her own. Grace is devastated at the thought of leaving her family, but does as her mother tells her. She sneaks back to the house, however, and asks her younger brother Colly to come with her. Grace and Colly wander through nearby towns, and Colly teaches Grace to act more like a man. One morning the man their mother was in a relationship with, Boggs, appears to drag Colly home. Grace smashes a rock into the back of his head, and she and Colly run off. She worries she has killed Boggs, but when she retraces her steps she sees that he has left. Grace decides that she must bring Colly back home so that Boggs will not keep coming after her. On their way back, Colly sees a dead sheep in a river, and when he tries to fish it out he falls in and is carried away. Grace goes into the river after him.

Grace is rescued by an old ferryman, and stays with him and his wife as she recuperates. When she leaves their home in December she notices many starving people walking along the roads in search of food. After Colly's death she has begun hearing his voice in her head, and having conversations with him. She adapts to the rough way of life on the road; she steals food, she sneaks into barns for shelter, and she learns to distrust the people she meets. This new lifestyle brings her despair, however, and she wishes she were back home with her mother and siblings. Grace eventually arrives in Donegal, and is mistaken for a boy named Tim by Mr. Boyd, a man who is organizing a cattle drive, or booley. She goes to work on the booley, along with Wilson, another cattle hand, Clackton, the leader of the booley, and Stockpost, the wealthy man who just bought the cattle. They pass through towns that are filled with people dying of starvation, and Grace feels lucky to have found a job where she receives food and shelter, and for which she will be paid afterwards. The booley is attacked by cattle raiders, however, and Grace sees Clackton shot by WIlson, who was working with the cattle raiders. She runs into the woods to escape. She is traumatized and exhausted by what she has seen.

Grace goes back to her solitary life as a boy trying to survive on the road. When she is putting on a little show in the town of Clones, a woman named Mrs. Gregor brings her back to her house to work for her. The Colly in Grace's head refers to Mrs. Gregor as Spiderwoman, because of the spider-shaped mole on her face. Mrs. Gregor/Spiderwoman makes Grace uneasy, and she feels like she is always watching her. One night Grace dreams she hears her mother's voice, and she crawls into Mrs. Gregor's bed, because she thinks she is her mother. Mrs. Gregor is enraged, and Grace has to flee the house.

Grace goes back to wandering, but a farmer discovers her sheltering in his outhouse and knocks her unconscious. When she wakes up she is in an unknown place, and all of her belongings except her knife are gone. It begins to rain, and then snow, and Grace is full of manic despair until she finds an abandoned hut. There is a dead woman inside, but Grace drags her outside and buries her, then turns the hut into her home. She stays here for a while in peace, and begins working on a bog road that is being constructed nearby, in Cavan. She gets her period for the first time, and the men she works with notice the blood on her pants and become suspicious of her. Some of them are positive that she is a woman, and she is followed home by two men. They attack her, but another man who worked on the bog road, John Bart, appears and fights them off. Grace had noticed Bart before because he had a crippled arm, but was still able to carry heavy rocks and fight well with a knife. Bart tells her that she has to come with him because it is not safe anymore. She is angry that she is being ordered around, but she goes with him.

Grace and Bart travel together, and the two form a strong bond, although Grace becomes frustrated with him often. They steal to survive, as times are becoming even harder as the famine worsens. Grace also begins dressing like a woman again, and tells Bart her real name. She threatens to go off on her own one night, and sits in front of an oncoming carriage. The driver thinks she is trying to rob them, and throws her a bag of money. She and Bart go to Athlone and buy new boots and cloaks. Bart meets up with a man he knows named McNutt, and the three of them leave town after McNutt tells them they are being followed by a detective. The three of them rob a wealthy family's home, and take up residence in a hut in the Slieve Bloom Mountains. One night they attempt to rob a coach, but McNutt shoots and kills the man and woman who were inside. In the aftermath they find their baby crying in the coach, and Grace is horrified at the crime she has taken part in. Back at the hut, Grace begins to see the woman's ghost, who she calls Mary Bresher. Grace notices that Bart is attracted to her, and that this makes McNutt angry. McNutt runs off, and when he returns he brings them to a house he had robbed, which he wants to rob again. A trap was set for him, however, and he falls into a pit and is beaten to death. Grace and Bart run off.

Grace and Bart journey to Limerick, where they stay in crowded, moldy rooms. They struggle to find food or money, and Grace becomes increasingly angry at Bart for bringing her to the city. After drinking some rum that they stole, Grace begins yelling at Bart. She tells him to stay away from her and that she does not love him. He tries to kiss her, and she hits him in the face. Grace spends the night drinking with different men in taverns, and when she wakes up hungover in a doorframe the next morning she realizes her new cloak has been stolen. When Bart finally comes back, he has been severely beaten, and all of his belongings have been stolen as well. They leave the city and head northwards, hoping to get to Galway. Bart develops a cough, and grows weaker and weaker. It is clear he has gotten the fever that has been killing many people. Grace finds a cabin for them to stay in, but there is no food, and she is overcome by starvation and cold. She begins to resent Bart, and to not care what happens to him. When Bart is dying, he walks out into the snow and disappears so he can die alone. Grace has a breakdown, and the Colly voice inside her head takes over her. "Colly" chases a crow for days, and then collapses. When he wakes up, he digs up a dead body and eats some of it before passing out again. He is picked up by a dead cart, and thrown into a burial pit.

When Grace wakes up again, she has lost her ability to speak, and the Colly voice in her head has vanished. She was rescued by a religious sect led by an enigmatic leader called Father, and made up of a few girls who are all called Mary. At first, Grace believes in what Father says: that the world is evil and filled with sin, and that all people contain the worm of Satan. Father becomes increasingly erratic, however, focusing on omens and enforcing harsh punishments. After a year, he invites Grace to come to his cabin to receive confession, which is something all the women do. Grace has been waiting to confess all year, because she feels haunted by the memories of all that she has seen and done. When she goes to Father's cabin, however, he tells her to undress. Grace refuses, and he becomes angry. On the third night, Grace undresses but will not let Father touch her. He begins raving and crawling on the ground, and Grace runs away and returns to the road.

Grace journeys back to her house, but when she gets there she sees that it is abandoned, and there is no sign of her family. She stays with a cousin, but he does not know what happened to them, either. Grace is surrounded by memories now that she is back home, and so she wanders again. The narrative jumps ahead nearly two years, and Grace is living in south Donegal with the man she loves, Jim Collins. She is expecting a child. The ghost of Grace's mother begins visiting her, and eventually dies in front of her, which allows Grace to finally get closure. She then realizes that she will soon be able to speak again, but she will only speak of the present, not the past. Her soul feels lighter now that she has begun to finally move on. The novel ends with her turning to Jim and speaking again for the first time, saying, "This life is light" (354).