In 1911, the story begins with Boy Charles, portrayed by John David Washington, who is desperate to reclaim his family's legacy. He steals a beautifully crafted piano from the Sutter family, a significant symbol of his family's heritage and strength. This piano, with intricate carvings representing African ancestors, holds deep meaning for the Charles family. After giving his family a chance to escape, Boy Charles attempts to flee in a train boxcar, but tragedy strikes when the Sutters catch up with him, ultimately burning the boxcar with Boy Charles trapped inside.
Fast forward to 1936, Boy Willie's arrival in Pittsburgh with his friend Lymon, played by Ray Fisher, marks a pivotal moment as they bring with them a truckload of watermelons. The plot thickens with the backstory of James Sutter's murder, in which Boy Willie seeks reparations offered by the Sutter family. They propose to grant him a portion of Mississippi farmland, spurred by a desire to settle old scores related to his father's tragic fate. Boy Willie is determined to sell the family piano to purchase the land, believing it essential to reclaiming their autonomy.
However, his sister Berniece, portrayed by Danielle Deadwyler, is vehemently opposed to this plan. Living with her young daughter Maretha and their uncle Doaker, played by Samuel L. Jackson, in Pittsburgh, Berniece sees the piano as a sacred artifact and a vital reminder of their shared struggles. Now in a relationship with local preacher Avery, Berniece’s bond with Boy Willie is strained, especially after previous conflicts involving the theft that led to her husband Crawley’s death.
The ongoing disputes between the siblings highlight the piano’s profound significance in both of their lives. While Berniece wishes to preserve it as a family memorial, Boy Willie views its sale as a crucial step towards freedom and self-sufficiency. Yet, the shadow of their father's legacy looms large, reminding Boy Willie of the importance of land ownership.
As supernatural elements come into play, Sutter's ghost begins to haunt the Charles household, raising tensions further, particularly for Berniece and Maretha. Berniece attributes the ghostly disturbances to Boy Willie's arrival and his disruptive ambitions regarding the piano. In contrast, Boy Willie dismisses her concerns. Meanwhile, Lymon finds himself drawn to Berniece, hoping for a fresh start.
The presence of Sutter’s ghost escalates, leading to a climactic confrontation with Boy Willie. In a bid to rid their home of the haunting, Avery attempts an exorcism, but it proves futile. Finally, Berniece courageously decides to play the piano for the first time in years. In doing so, she invokes her ancestors, seeking their aid to banish Sutter’s spirit and protect her brother. A turning point occurs as Boy Willie begins to understand Berniece's perspective, encouraging her to continue playing.
Ultimately, Boy Willie reconsiders his intentions regarding the piano and opts not to sell it. Instead, Berniece takes on the role of mentor, teaching Maretha how to play, thus passing down their family's musical legacy. In one last attempt to connect with the land, Boy Willie returns to the now-publicly available Sutter farmland, connecting with his heritage before moving forward. Grasping the dirt as his father once taught him, he departs, leaving behind a mix of hope and resolution.