In Edwardian London, during the summer of 1903, a quiet Fulham shop is shattered when its Scottish owner is stabbed to death and the shop is set ablaze by the enigmatic composer George Harvey Bone. He stumbles into the street and eventually makes his way back to his basement flat at 12 Hangover Square in Chelsea, where his girlfriend, Barbara Chapman, and her father, Sir Henry Chapman, await him. Bone privately confesses to Dr. Allan Middleton that there is a troubling gap in his past, revealing that there is "a whole day missing" from his memory. This unsettling confession plants the seed of doubt and hints at a mind fraying under pressure.
On August 29, at a smoky, lower‑class pub’s smoking concert, Bone encounters a would‑be star named Netta Longdon; Netta Longdon is ambitious and calculating, a singer who wants to ride Bone’s talent to bigger fame. Their meeting is casual at first, orchestrated through Bone’s friend, Mickey. Netta is not impressed by Bone’s music or his status, yet she recognizes the pull of his genius and the leverage his composing ability offers her. Barbara, meanwhile, is put off by Bone’s fixation on Netta, and Dr. Allan Middleton quietly tries to get closer to Barbara, sensing a dangerous pattern in Bone’s behavior. As stresses mount, Bone experiences another amnesia episode and in a chilling moment nearly strangles Barbara, underscoring the fragility of his grip on reality.
Tensions erupt on Guy Fawkes Night when Bone finally acts on his darker impulses: he murders Netta and, wrapped in anonymity and darkness, drags her corpse through bustling streets to place it atop the largest bonfire. With no memory of the crime, Bone is able to persuade the police of his innocence, but Middleton remains wary and resolved to intervene if needed. The detective’s suspicions drive him to confront Bone on the eve of what should be a triumph, a concerto premiere that could cement Bone’s legend or reveal his guilt.
The confrontation escalates as Middleton insists on stepping in for Bone’s own protection, only to be locked inside the flat while Bone proceeds with the performance. Midway through the concert, a workman’s cry and the arrival of police shift the balance, giving Middleton a chance to escape and rally reinforcements. Bone’s memories surge back in the heat of recognition, but he chooses to press on, asking Barbara to carry the performance forward as ominous danger closes in. When questioned separately, Bone lashes out, hurling a gas lamp and igniting the room. The building erupts in flames as he returns to the piano, determined to finish the last notes of his blazing concerto.
Outside, [Sir Henry Chapman], Barbara, and Middleton watch the theater burn, the air thick with smoke and fear. Middleton’s quiet, stark question—whether Bone should have escaped—drums through the night: > "It's better this way, Sir." The concert hall fills with flame and smoke as Bone’s final notes echo over the chaos, leaving the audience and musicians fleeing while the tragedy of Hangover Square lingers in the notes of a haunted symphony.
