Gravely ill and given only until Christmas Eve to live, the aging lord wishes to savor one last moment of familial unity, but beneath the festive veneer lies a web of animosity and unresolved tensions.

The guest list includes Mrs. Carstairs, the wife of the Minister's assistant; Lady Camilla Prendergast, who grew up alongside Robert; and the pastor's daughter, a lifelong friend of the Warbeck family.

Among the long-term residents of the castle are Dr. Bottwink, a European émigré historian studying the Warbeck archives, and the loyal butler Briggs, who struggles to prevent his daughter Susannah from making an outburst that might disrupt the gathering.

The investigation grows increasingly complex as the connections between the guests reveal unexpected secrets, hidden grievances, and troubling alliances, leaving the motive for the murders shrouded in mystery.

As tensions mount and the body count rises, it becomes clear that the key to the puzzle lies with Dr. Botwink, the outsider historian, whose unique perspective allows him to untangle the intricate web of relationships and uncover the truth behind the unfolding tragedy.