Situational irony - Ana Dakkar is the descendant of Nemo
The novel introduces Ana Dakkar as a skilled student who specializes in communication with marine life. After the sudden attack on Harding Pencroft Academy, Dr. Hewett insists on the importance of Ana’s safety. Midway through their escape in the middle of the ocean, he drops a bomb on his students. All the stories from Jules Verne about Captain Nemo are actually true and Ana is the direct descendant of Nemo, and the only one who can unlock his hidden secrets. This is an unexpected twist to the story and creates situational irony.
Situational irony - the truth about Ana’s parents’ death
After they arrive to the hidden island, Ophelia and Luca reveal the truth about Ana’s parents’ death. Her parents didn’t die in a diving accident, as she believed. Instead, they were killed by the main secret left by Nemo - his submarine Nautilus. They were killed when they tried to forcefully enter it. This comes as a shock to Ana and provides an unexpected twist to the novel, creating a situational irony.
Situational irony - Dev the villain
As the characters get attacked by the Annorax submarine of the LI, the captain of it gets in contact with the Nautilus. The captain of the enemy submarine is none other than Ana’s brother, the one whom she believed to have nobly sacrificed himself warning the people at HP, Dev. This is the main unexpected plot twist in the novel and creates situational irony.
Irony of the necklace
The black pearl necklace the Ana wears around her neck is the only last remainder of her family. She wears it all the time as a comfort. All the while, she suspects that they have a betrayer among the crew, not realizing that she is the one who unintentionally betrays them by wearing the necklace - the necklace which Dev gave to her to use her vulnerability and grief against her.
