Summary of Chapter 17
Rio finds True alive and well near the temple, and the two embrace. Under the temple trees, True confesses that he heard Rio use her real voice during the ceremony of the Divide, and he knows she is a siren. The two kiss under the trees. Rio and True decide to hijack a gondola and head to the deepmarket to see if they can help the people trapped there. They discover a crowd at the gates being kept at bay by peacekeepers. Maire appears suddenly and explains that the people in the deepmarket were knocked unconscious by air pressure and then drowned. She uses her voice on the crowd to make them disperse.
Rio mourns the loss of the deepmarket, her mother's ring, and her chance to prove herself in the swimming lanes. True realizes that she is not planning to stay below, and Rio confirms this. The two walk hand in hand toward the temple, and notice that all the metal leaves have fallen off of the trees. Atlantia is falling apart, and so is Rio. She worries about the growing number of people who know her siren identity - Justus, Maire, and now True.
Summary of Chapter 18
According to a special broadcast by Nevio, hundreds of people died in the deepmarket breach. They will be sent up through the floodgates in groups, and Rio sees her chance to escape Atlantia through this method, though she feels guilty for benefiting from a tragedy.
Rio sneaks into the morgue with her air tank and disguises herself among the bodies. She has a moment of grief when she realizes she will never see True again, then the water starts to rush into the room. Rio fears that perhaps Maire tricked her into doing this on the orders of the Council, who might want to get rid of Oceana's single remaining daughter.
Rio sees the other bodies moving through the water to a blazing bright light, and wonders if this is the third miracle. Suddenly, the brightness fades and the water levels lower. Rio’s escape attempt has been discovered.
Summary of Chapter 19
Rio, panicked, wonders how her escape attempt was discovered. Her head bobs under and water floods into her mask, choking her. When the water receded from the room, peacekeepers take her to a small room which is paneled in rare and expensive wood.
Maire comes in. She says that she told the Council that Rio only wanted to visit her sister and asks questions in such a way that Rio realizes that Maire wants her to reveal her hidden siren identity. Rio does not do this.
Maire explains that the people from the Above are tired of helping the people of Atlantia. The underwater mines are nearly gone, and the people of the Above have decided to stop sending food if they will get no ore back. Maire also makes cryptic mention of the deepmarket before Nevio walks in the room.
Rio observes the coldness between her aunt and the Minister. Maire tells Rio that this is her one chance to get to the Above, and Rio reveals the secret she has kept all of her life – that she is a siren.
Summary of Chapter 20
Nevio, stunned, orders Rio to follow him to his office. As the two hustle behind him, Maire warns Rio to save her voice. Nevio is delighted with this new discovery, which unsettles Rio. He asks who knows, and Maire tells him that outside of her immediate family, only Justus and True Beck know. Alarmed at the thought of anything happening to True, Rio tells them to stop – and amazingly, the two sirens do. Nevio is impressed with her power. Rio says she wants to go Above, and Nevio says that she will.
As the two women leave, Maire explains that this is Rio’s best chance to get to the Above. She also notes that they are running out of time to save Atlantia – there was another breach in the plaza last night, a long slow drip that cannot be repaired.
Angrily, Rio asks how Maire can cooperate with Nevio after he killed her sister. Maire simply replies, “You know what he is,” indicating that she also knows Nevio is a siren. Nevio took the communication shell from Oceana just before her death, but he has never been able to use it.
Maire explains to Rio that she must use her voice sparingly, because this will imbue it with an enormous amount of power. Already Rio has the most powerful siren voice Maire has ever seen.
Maire also explains that Nevio is sending all the sirens of Atlantia on a mission to the Above, to remind the people there of their duties to the people Below. It has been two weeks since the people of the Above stopped sending food and raw materials to Atlantia, which is why they are unable to repair the leaks that keep appearing. Maire also reveals that it was the people of the Above who place the mines in the water.
Rio always wanted to leave Atlantia, but she never wanted the city to die. She meditates on the beauty of the city, and agrees to cooperate with Maire to find a way to save it.
Summary of Chapter 21
Rio and Maire are led to a transport with the other sirens, who are tame, Council-trained creatures clad in unusual clothing and makeup to make them seem otherworldly to the people of the Above. Rio thinks that this makeup is a bad idea, that it will make the sirens seem less relatable, but she allows them to apply it to her face.
Rio asks about the Above, and Maire says that it is a large island surrounded by many other islands. Other sirens remark that that the people of the Above consider sirens to be gods, and that siren voices are even more powerful on the Above. Rio sees Maire’s dark reaction to these statements, and wonders about their veracity.
Nevio comes in to give a pep talk to the sirens, openly identifying himself as one of them. He extorts them to remind the people of their duty, and leads them through a recitation of the sacred words of the Divide. Nevio departs, and Rio notices that there is no handle on the inside – no way out. Rio cannot shake the feeling that something is very wrong here. Unexpectedly, Maire gives her a letter from Bay. In the letter, Bay explains that she went Above to prevent Rio from doing so – sirens cannot survive long outside of the Below. Moreover, the people of the Above hate sirens and kill them on sight. Oceana never told Rio this information because she did not want to break her daughter’s heart. Bay explains that she left the money so Rio could take care of herself, and asked Maire to look after her as well.
Maire notes that both Bay and Oceana always underestimated Rio; they never understood her potential as Maire does. Suddenly, the door of the transport opens, and someone else is ushered inside. It is True Beck.
Once again, Maire is found at the scene of a major tragedy, this time the deepmarket breach. Rio suspects that her aunt may have had something to do with this major tragedy, but she cannot be sure.
Rio decides to try to reach the Above through the floodgates, one of the more risky ways. Though the opportunity to impersonate Oceana in the swimming lanes was denied to her through the destruction of the deepmarket, she still has the opportunity to reenact her mother's final exit from Atlantia, though of course this is not her full purpose in escaping in this manner. This action draws a sharp parallel between mother and daughter. The main difference is that Rio's escape attempt was circumvented by Maire.
We never find out exactly how Maire knew that Rio attempted to escape in this particular batch of bodies, which contributes to the characterization of Maire as a powerful woman privy to numerous secrets. However, it also becomes clear that she is not in cahoots with Nevio, who is clearly established as a villain due to his hidden siren abilities. He clearly considers Rio an object to help him achieve his aims; Rio notes that he seems to look at her like a sculpture or a line of scripture.
A number of secrets are revealed in this section. The Above and the Below are only two of many. The Above now has clean air, and sirens cannot live out of the water. This final detail may be an allusion to Hans Christian Andersen's The Little Mermaid, in which the titular character longs to be human to marry her beloved prince, but suffers horribly in this mission: she has given up her voice for human legs that cause her intense pain every time she takes a step, and she is cursed to dissolve into foam if her prince marries another (which he does). Like the little mermaid, Rio can only survive in the underwater world, as much as she longs for the Above.
This section also contains a great deal of foreshadowing. The leaves that have fallen off all the metals trees of Atlantia seem to suggest that a great catastrophe will befall the city, and Maire's has a sarcastic and unsettling reaction to the other siren's claim that the people of the Above will treat them like gods. The narrative introduces a number of mysteries (why is True on the transport?) and raises the stakes, heading toward a final climax.