Twins play a major role in the plot of the story; Sadie and Sarah are twins, as are Ellery and Ezra. In both cases, their personalities are very different, and Ellery thinks often of how she is similar to Sarah, who disappeared, and expects that the tragedy of Sadie and Sarah might repeat itself in her and her brother. The book opens with a discussion that includes an offhand remark about being the wrong twin, only for that idea to be the summation of the book’s final tragedy. To Ellery, being a twin means being marked for tragedy.

Though similar to the motif above, a sense of things echoing, repeating, or mirroring each other is just as pervasive and distinct in the book. Malcolm and Ellery are coping with the same kind of trauma; Daisy and Sadie both suffer from survivor’s guilt; the past repeats itself in Lacey and then Brooke’s murder. Even the name, Echo Ridge, is deliberate in its assertion that violence reverberates across generations.

In Chapter 19, Ellery observes a broken Hummel figurine of a little girl that belongs to her Nana. Sadie broke it, but Sarah took the blame.