Leviathan. His cliffhanger ending was quite effective in getting me to want to know what would happen next. The adventure resumes almost immediately after the end of the first book.
The Leviathan makes it to Constantinople to complete it's secret mission. The ships that damaged it have already arrived, and have offered themselves in service to the Sultan. The Sultan has stayed neutral in the war so far, and they are hoping to sway him to enter on behalf of the Clanker forces. Dr. Barlow follows through on the arranged meeting with the Sultan to offer the apology gift to replace the ships that were ordered but not delivered due to the start of the war. Understandably, this breach of contract had angered the Sultan, as he had paid quite a bit of money for them. However, the meeting is sabotaged by some of the court when the egg that was to be the Sultan's gift was crushed. In order to ease the Sultan's anger and buy time to stay in the city, Dr. Barlow offers him the Leviathan itself. It also gives the Darwinists a chance to come up with another plan to reach the enemy ships.
In the mean time, Alek and his men know that they must leave the Leviathan before it departs from Constantinople or face being prisoners of war. Deryn assists them in this effort, though it is technically treason. Since Deryn is aware of Alek's secret, she is also aware that he could bring an end to the war. She has also fallen in love with him, so that is also a factor in her decision. After the escape Deryn is called before the Captain, she is terrified that her treachery has been discovered. Instead, she is surprise to be awarded a medal of honor and given a top secret mission.
While Deryn is fulfilling her mission, Alek is making contact with a group of rebels that wish to overthrow the Sultan. Deryn's fellow soldiers are captured during the mission, so she heads into town to find Alek. Together with the rebels, Alek and Deryn hatch a plan to defeat the Sultan.
Once again, Westerfeld's descriptions of the unique machines and creatures that populate this world are stunning. The combatants are much closer to each other during battle in this book. The Orient Express even makes an appearance. The climax of the novel is built well, and stops at a very satisfying moment. It lets you know that there is more to come, while not dropping the audience as roughly as the end of Leviathan did. This series is entertaining for adults and kids alike. I look forward to reading the final chapter of the tale, Goliath when it comes out.