A film about the search for a murderer linked to a play about a search for a murderer based on a real life case. With more layers than the massive cake that murder victim Leo Köpernik falls into at The Mousetrap‘s 100th performance celebrations, See How They Run blends a real life case of child abuse with the world’s longest running play and a few killings on top.
If you just want to know the identity of Leo Köpernik and Mervyn Cocker-Norris’s killer, it’s… Dennis the usher! For more on the plot, other suspects, and reality vs fiction, scroll down.
“It’s a whodunnit. You’ve seen one, you’ve seen them all,” begins the narrator, who turns out to be the first murder victim: film director Leo Köpernik. We’re in London in 1953, and the play The Mousetrap has reached its 100th performance — the cast and producers are celebrating with a party. Agatha Christie herself cannot attend but sends a giant celebratory cake…
The Mousetrap takes as its driving force a real life story: the cruel treatment of Welsh siblings at the hands of their foster parents, resulting in the death of one of the children, Dennis O’Neill, in 1945. In the play, which unfolds at a snowed-in manor house, the killer is also one of the surviving siblings, and pretends to be a police inspector investigating a murder that he actually committed (the victim is his foster mother).
In See How They Run a film of The Mousetrap is in the works — the rights have been sold to producer John Woolf of Romulus Films, though a clause prevents him from making the movie until six months have elapsed after the end of the play’s first London run. Currently the play’s popularity is making the film look ever more unlikely, helped by the warning the audience is given not to give away the ending to anyone — which ensures intrigued Londoners must buy a ticket to watch it, further prolonging its run.
Meanwhile Leo Köpernik has been taken on as the film’s director, and has been locking horns with pompous writer Mervyn Cocker-Norris over what the content should be. (Leo wants a “violent death in the opening frames”.)
At the party, attended by stars of the play Richard “Dickie” Attenborough and his actress wife Sheila Sim, Köpernik and Attenborough get into a fight over Sheila. Köpernik falls into the cake and goes off to the costume department to borrow a clean outfit, but while in there he’s murdered by a man in a long coat and felt hat. His body is then posed on a sofa on the stage, with his tongue cut out.
John Woolf, the film’s producer: he is desperate for the play to close so he can make his film, as he can’t start production until six months after the end of the play’s initial London run. A murder in the building might lead to the closure of the play (sadly Petula Spencer, the play’s producer, is very much of the “show must go on” school of thought). Woolf is also being blackmailed by Köpernik, who knows about his affair with his assistant Ann — he’s forced to pay for Köpernik’s expensive stay at the Savoy Hotel to avoid his wife finding out about Ann.
Mervyn Cocker-Norris, the film’s screenwriter: he is furious with Köpernik for the direction he wants to take the film; furthermore, Mervyn is overheard by the manager of the Savoy Hotel threatening to kill Köpernik.
Inspector Stoppard: he had previously been married to a homely-looking, dark-haired, glasses-wearing woman called Joyce; she left him while pregnant with an American man’s baby. Köpernik had an illegitimate son by a woman called Joyce, who matched the description of Stoppard’s ex-wife. Stalker comes to believe the two Joyces are the same woman (they aren’t!) and that Stoppard is the killer. When he leaves the auditorium half way through the first post-murder performance of The Mousetrap, and a few minutes later Cocker-Norris is murdered on the theatre stairs, she chases after her boss and bashes him over the head.
Dickie Attenborough: he fights Köpernik at the party, eventually throwing the director into the giant cake sent by an absent Agatha Christie. The fight is over his wife Sheila; Köpernik is drunk and objectionable, and reticent about offering her the chance to reprise her lead role in the movie.
The real killer’s motive
In See How They Run, Dennis is the survivor of two Welsh siblings, his younger brother having been killed aged 6 by their abusive foster parents. The Mousetrap is based on his and his brother’s story. Dennis’s motive is to stop the play and the film of the play being made; it is his story and not for anyone else to tell it.
Dennis had killed Leo Köpernik after overhearing him say “without me there is no movie”. Mervyn also had to die as he was writing the film. Dennis now plans to kill Agatha Christie to make people listen.
The film’s ending
John Woolf, Ann, Petula, Petula’s mother, Dickie Attenborough and Sheila Sim turn up at Agatha Christie’s country house, after being sent dinner invitations faked by Dennis.
In the drawing room, Dennis takes them hostage and threatens to kill Agatha Christie, who he claims to have rolled up in a carpet (actually it is Edana, the film producer John Woolf’s wife). He is distraught that his family’s story is being told by other people when it is not theirs to tell.
They offer to stop the play and the film, and are sympathetic to Dennis’s plight; Sheila says he’s owed an apology.
Agatha Christie herself then comes in with a big tray of tea cups. She is most particular about who should get which cup, but the tray spins around on the table. She tells Dennis she cannot be told what to write or not. The butler, after drinking one of the cups of tea, keels over dead.
Inspector Stoppard and WPC Stalker know who the killer is; he sends her to the office to do paperwork and drives to Christie’s house through the now-falling snow. He arrives and turns out the lights. Outside, en route to the country house, WPC Stalker’s car crashes at a snowy junction.
Sheila makes a molotov cocktail and throws it. The inspector shoots Dennis in the leg; as Dennis goes to shoot back, the inspector’s gun jams. WPC Stalker runs in to the house and knocks Stoppard out of the way. Agatha bashes Dennis over the head and kills him; an injured Stoppard tells Stalker he does now trust her.
“A shoot out and a big explosion, says John Woolf to Petula. “Perhaps it’s for the best that Mervyn wasn’t alive to see it.” (This scene is a replay of one described earlier in the film by Köpernik, who was a fan of instant violent mayhem in movies. Mervyn had been horrified by the idea.)
Later, Stalker takes her sergeant’s exams and passes with flying colours. Stoppard gets a King’s Police And Fire Service Medal. The commissioner gets a knighthood.
Why See How They Run?
See How They Run is a line from the nursery rhyme Three Blind Mice, which was itself the title of a radio play (and short story) which Agatha Christie wrote based on the real life case of the O’Neill brothers. Three Blind Mice was later turned into the play The Mousetrap.
Reality vs fiction
The play The Mousetrap is based on the true story about the abuse of two brothers, Dennis and Terence O’Neill, at the hands of their foster parents. In 1945 Dennis died as a result of the abuse; the case caused shockwaves and led to new rules on the welfare of fostered children. In the play, the children’s surname is changed to Corrigan, and the killer turns out to be the eldest Corrigan child, now grown up. He pretends to be an inspector investigating the very murder he committed (the victim is the foster mother who abused him and his siblings).
The play’s first cast did indeed include Richard Attenborough and his wife Sheila Sim.
It is also true that film of The Mousetrap could not be made until the first London run ended — it eventually closed in 2020, and then only because of the COVID shutdown.
In See How They Run there is discussion of an urgent real life murder case, The 10 Rillington Place murders. Serial killer John Christie murdered several people, eventually blaming the murders of his neighbour Timothy Evans’ wife and daughter on Evans himself. Evans was hanged, though eventually pardoned. In the 1971 film 10 Rillington Place, Christie was played by… Richard Attenborough.
Inspector Stoppard gets his name from the playwright Tom Stoppard, who wrote The Real Inspector Hound, which both parodies whodunnits (particularly The Mousetrap) and sits the play within a murder mystery.