Murdoch realizes that a detailed diorama of a Toronto street depicts a murder. However, the artist is nonverbal, and Murdoch must figure out how to connect with her to help solve the crime.
Tropes:
- The Alibi: Mr. Galbraith provides a pretty airtight one when accused of having killed the victim while everyone else was watching the parade.Mr,. Galbraith I wasn't watching the parade.Murdoch: just as I suspected.Mr. Galbraith: I Play in the Orange Lodge Band detective. I was in the parade.
- Asshole Victim: Everybody in the street hated the guy and everybody had a reason to kill him. They were all relieved when he was gone and nobody reported that he was missing.
- Awful Wedded Life: The Galbraith's don't get along very well, and Mrs. Galbraith had an affair with the victim.
- Big Brother Instinct: Lydia's brother Bert acts as her caretaker and is the only person in the neighborhood who makes the effort to understand her. He provides her with the materials for her model-crafting, knows how to soothe her when she's upset, and according to Mrs. Galbraith, his devotion to Lydia cost him his marriage when his wife demanded that Lydia be institutionalized.
- Carpet-Rolled Corpse: The victim disappeared along with his landlady's carpet (she thought he'd stolen it), as his blood was on it. The carpet is used to help identify the corpse once it's finally found.
- Chekhov's Gun: Or rather, chekhov's trumpet. Which is used to prove that the murderer wasn't watching the parade, due to his not knowing that Mr. Galbraith had been playing a trumpet, instead of his usual trombone that day.
- "Eureka!" Moment: When Murdoch gets Lydia to start putting her cardboard cut-outs back to the houses they came from, to get past the lack of facial identification and see who is left by process of elimination.
- Does Not Like Guns:
- Mr. Galbraith owns the rifle that was used in the murder but claims it was his father's and he's never used it in his life he's telling the truth.
- Mr. Draper also denies that he's ever touched a gun in his life.
- I Regret Nothing: The killer, when arrested, defiantly claims to have done the neighborhood a favor.
- Idiot Savant: Lydia is regarded as an 'imbecile' (in the parlance of the era) and is effectively mute, but has total recall and a phenomenal ability in making models. When she makes a scale model of her street with a tiny figure holding a rifle at the window, Murdoch realises she has witnessed a murder and reconstructed it in the model. However, because she cannot distinguish faces and has thus not included any facial details on her models, Murdoch has no way of identifying the figure at the window and has to work out a means of communicating with her to discover what she knows.
- Imagine Spot: In his efforts to puzzle out the mystery, Murdoch at one point imagines himself standing within Lydia's model of Cherry Lane as though he has been shrunk down to its scale. He's snapped out of it when Crabtree comes in and begins talking to him about the case, briefly seeming to lean over model-Murdoch to address him.
- Kindhearted Cat Lover: Felix Roach, who is well-liked by his neighbors, doted on his cat and buried it in a makeshift coffin which is briefly believed to be the grave of whoever was murdered. he killed the victim to avenge the death of his cat.
- Your Other Left: Murdoch says this to Crabtree when he is directing him as they attempt to reconstruct the position of the rifleman.
