Arthur is a veteran stagehand at the Grand Lyceum Opera House in 1920s London. During a high stakes opening night performance, he witnesses a shadow in the rafters that does not belong. When the lead tenor dies on stage in a gruesome accident involving a heavy chandelier, Arthur realizes it was not a mechanical failure but a calculated murder. To catch the killer, he must navigate the hidden world of trapdoors, pulleys, and secret passages behind the velvet curtains before the final bow.