Assuming the role of Inspector Hound, Moon instructs the other characters to return to where they were when the shot that killed Birdboot was fired. Moon is shaken up by the whole incident. He formulates an explanation of Birdboot’s/Simon’s death. Simon suspected Magnus of being the madman, and just as he was about to pronounce why, Magnus shot him to keep him quiet. But Magnus asks Moon what motive he would possibly have for killing the unidentified man, played by Higgs.
In another confusion between the play and reality, Moon realizes that he is the only person in the room who had any motive to kill Higgs — his motive, of course, was to become the first-string theater critic. So, he denies knowing the identity of the dead man. Mirroring Inspector Hound in the original scene, Moon rushes to place blame somewhere. His story isn’t much different from the original scene. The dead man is McCoy, against whom Simon held a deep-seated grudge. Simon was killed by Felicity out of revenge for his falling in love with Cynthia. When Moon finishes detailing his hypothesis, Felicity says that the story makes no sense.
Magnus starts to develop his own hypothesis. Couldn’t the same person have killed both Higgs and Simon/Birdboot? He observes that the Inspector/Moon hasn’t produced any proof for his claims. For example, why should he trust that the dead man really is someone named McCoy, as the Inspector claims? The whole tale seems fantastical.
Magnus suggests an alternative. Suppose the madman killed the unidentified man for "private reasons" but didn’t have time to dispose of the body. He returned to the scene of the crime to do so, masquerading as Inspector Hound. He did not expect Simon — who somehow knows the real identity of the dead man — to be there. When Simon was about to reveal the identity of the dead man, and implicate the fake Inspector Hound as the madman, the fake Inspector Hound shot Simon to death.
Magnus asks Moon, “I put it to you, are you the Real Inspector Hound?” But Moon is still interfacing with the characters as the theater critic, not as Inspector Hound. So logically he responds, “You know damn well I’m not!” And at that admission, all the characters agree that Inspector Hound/Moon is the real madman.
Another twist develops. Magnus is not the real Magnus Muldoon. He is the Real Inspector Hound. But Moon also recognizes him as Puckeridge, the third-string theater critic. Magnus/Puckeridge threatens to shoot the fake Inspector Hound/Moon. Moon now understands that, just before his death, Birdboot was trying to tell Moon that it was Puckeridge who killed Higgs. But Puckeridge shot Birdboot before he was able to warn Moon.
Moon tries to run, but he is shot by Puckeridge. Magnus reveals that he lives a double life. He is not just the Real Inspector Hound, but also Albert, Cynthia’s long lost husband. Of course, we know by now that he could be considered to be living a triple life, since he is also Puckeridge. Moon, dying, says, “Puckeridge, you cunning bastard,” and the play ends.
The play’s ending twists and turns at a rapid-fire pace. All at once, two murder mysteries are solved. First, in the play-within-a-play, Inspector Hound turns out to be the madman and Magnus turns out to be the real Inspector Hound. Magnus also turns out to be Albert, Cynthia’s long-lost husband. Second, outside the play-within-a-play, Puckeridge (playing Magnus) turns out to be a murderer, with the motive of moving up the ladder of theater critics. Even though order is restored to Muldoon Manor, the offstage universe remains chaotic — the madman of the London theater scene, Puckeridge - is alive and well at the end of the play.
As discussed in previous sections, The Real Inspector Hound parodies The Mousetrap by Agatha Christie. The groundbreaking twist in Christie’s play was to reveal that the detective — the traditional adversary of the murderer — was the murderer himself. This is exactly what happens at Muldoon Manor in Stoppard’s play: Inspector Hound turns out to have murdered both the man on the floor and Simon. But even as Christie pushed the genre out of it traditional structure, she still restored order to the fictive universe by the end of the play, adhering to traditional narrative bounds.
Stoppard’s innovation is to end the play without restoring order to the universe. Sure, at the Muldoon Manor, the real detective, Magnus, resolves the crime. But in the London theater universe inhabited by Birdboot and Moon, there is no detective at all. The character Magnus, who saves the day in the play-within-a-play, is played by the third-string critic Puckeridge, who, offstage, is a murderer. He kills Higgs, Birdboot, and Moon so that he can rise to the top of the theater scene. When Puckeridge/Magnus kills Moon/Inspector Hound, the other characters view it as an act of justice. But at another level it is a complete injustice, a murder, not just of Moon but of the traditional structure of detective fiction.
As Carlson notes, the “hall-of-mirrors effect is in itself highly destabilizing of the normal world of detective fiction, but Stoppard’s subversion is particularly so because it results in the removal from the fictive world of the key figure who provides an intellectual and moral centre for that world, the detective.” Even though detective fiction features chaos and criminals, there usually is a figure that the reader can trust to restore moral and intellectual order. But in Stoppard’s play, we are never given that satisfaction. The play ends with Puckeridge, the murderer, on the loose, and the other characters believe him to be an arbiter of justice.
Though Stoppard’s play is at face value a "whodunnit", we are not so concerned with the question. We really can’t be, as Stoppard’s work piles layers upon layers of reality that are nearly impossible to tease apart. Carlson notes, the questions that really matter are ontological (the nature of being) and epistemological (the theory of knowledge) in nature. What actually happened? What can we be sure of? On what level of reality did something occur? The traditional bounds between fiction and reality — stage and audience, actors and characters — do not help us string together of a coherent explanation of the plot. The universe is unordered all the way through to the end.