Opening sentence informs the reader that this is the chapter when Briony “will commit her crime.”
We are back a little bit in time, to the search party moments earlier, and Briony is searching for the twins on her own. Happy that Cecilia is under the protection of Leon, Briony heads in the opposite direction of Robbie, the “maniac,” and towards the lake. Before Briony leaves the lot nearest the house, she voyeuristically observes her mother in the window. She contemplates entering the drawing room and waiting with her mother, cuddled and secured, for the rest of the crew to return with the twins. Determined, however, that she is no longer a child, she abandons these infantile desires and continues with her search for the twins.
Following a hunch that the twins may be in the temple in the lake, Briony makes her way towards the island. As she nears, she thinks she spots a bush or tree in the temple that she is unfamiliar with. As she closes in, the bush splits into two and it is then that she realizes it wasn’t a bust at all, but two people.
Lola calls out, unsure, for Briony. At this moment, a larger figure dashes from the scene, leaving the terrified Lola rocking in fear and shock on the floor of the temple. Without clearly saying it, Lola was in the process of being raped. Briony approaches her older cousin and immediately does her best to comfort her. It is at this point that Briony begins to unravel her “crime.”
At first, Briony repeatedly asks her cousin: “Was it him?” But Lola never answers. After repeated attempts to have her cousin identify her assailant, Briony realizes Lola doesn’t know who it was, creating an opening for her to plant the notion that it had to be “the maniac.” Lola herself continues to be unsure, but does not act with any sort of defiance or authority over Briony's accusations. She explains to Briony that she never did see the man that was raping her. She was attacked from behind and her eyes were covered during the assault. Briony ignores this doubt, inferring it had to be Robbie. She tells Lola about the scene she witnessed in the library between Robbie and Cecilia, further supporting her claim. Briony is now determined that the rapist must be Robbie.
She comforts Lola to the best that she can, who is still contending the doubt in Briony’s claims. The two eventually leave the temple and make their way back to the house. Before they can ascend the embankment (Lola cries she is too weak), Leon and Cecilia appear on the bridge. Leon carries Lola without asking questions; Cecilia remains silent, attempting maternal care that goes ignored. As they walk to the house, Briony expels the tale she is now “certain” of exactly what happened.
Briony's interpretation of Cecilia and Robbie's love leads her to believe she must "protect her sister." This is an inversion to the way that Cecilia used to protect Briony after nightmares, and instead of protecting her by imploring "come back," the failed attempt causes her to go away. The crime she is about to commit is smothered in good intentions, however misguided they may be.
Again, we have the theme of misunderstanding or misinterpreting a sensory experience. What Briony "sees" by the lake isn't enough to overcome what she "imagines" to be true. This visual confusion in the dark (literally and figuratively) contributes to Briony's false accusation of Robbie, proving she trusts her literary instincts more than visual data. Briony's crime then, is not that she blatantly lies, but that she confuses fact for fiction through her talent for artistic creation.
On page 150, it is noted that Briony's childhood ended "in the dark." What began as a scene in a well-lit nursery, ends with a scene in a darkened wilderness. McEwan is making obvious references to literary allusion here, specifically to William Blake's Songs of Innocence and Experience--the lamb and the tyger. Briony is now a participant in real life, in the wild, by a lake, instead of a player in a childhood fairytale in a nursery.
The rape happens near a temple "on an artificial island in an artificial lake." Even the surroundings are made up, but still 200 years old. Just like the art of writing and story-telling, what is perceived as natural and ancient, can be one without necessarily being the other.
Briony is not the only one to commit a crime here. Lola's silence when she very well knows Briony is making up her "knowing" of what she saw is just as indicting. As well, when the authorities arrive and the adults are involved, everyone relies on the testimony of one thirteen-year-old girl. The adults ignorance in such matters and failure to pursue proper truth can warrant just as much blame for Robbie's false arrest, if not more.
Finally, Robbie is described as the true hero, coming down the embankment towards the house with the two twins at his side. This is a foreshadowing and further representation of the idea that the Quincey boys are interchangeable with Corporals Nettles and Mace. Here we have Robbie leading them from the wilderness back to the home front in safety. Robbie as "hero" to the narrator's eyes stretches beyond that fateful night in 1935 and into the war. It is Nettles in the end who shares Robbie's letters with Briony so she can accurately write the war section of the book, and it is Pierrot in the end who finally organized the "Trials of Arabella" to be played out in full.