The fourth book from the Underland Chronicles series was published in May 2006. Gregor and the Marks of Secret is another fantasy novel of Suzanne Collins. By the fourth novel Gregor and the Marks of Secret the readers are well aware of all the characters and the story of the Underland. The book begins with Gregor who is busy in the preparation of echolocation training which he will receive in the Underland. Gregor travels to the Regalia city where is informed about another Prophecy which is called the Prophecy of Time. He is anxious to know more about it but whenever he tries to ask anyone about it, no one gives him an answer. Gregor than finds out that Bane has now turned 8 and also attacked Riperd because of the continuous taunts on Bane by Riperd. One more thing revealed was the real name of Bane which is actually Pearlpelt.
Later on Gregor gives up on his training of echolocation and assumes that he is not in need of it. But one day when he is attacked by rats he fails to fight efficiently as there was no light and he also drops his flashlight because of which he is unable to see and then he realizes how important the echolocation training is.
The story now goes a little fast with Gregor escaping from the fight, meeting his mom and heading for the party where he meets Luxa and dances with her. While hanging around with Luxa he realizes that he likes her but before the admiration can proceed further they get the news of mice being in danger and decide to go for their help. Uncertain death of bats and a following Earthquake made Gregor, Luxa, Nike, Ares, Boots, Thalia and Ripered suspicious about the matter. They reunite to find the reality and an investigation reveals that Bane is making out plans to conquer the Underland.
The reunited team moves on to save the Underland and head to a volcano where they discover a colony of nibblers. On trying to escape they feel suffocated and due to the air shortfall they drop down on the ground. This clarifies what the prophecy actually read and how the nibblers turned out to be a trap. The misunderstanding of Luxa being the queen in the prophecy also got cleared as the indication was towards the volcano and not Luxa.
The volcano erupts and there is smoke everywhere. When Gregor opens his eyes he is in a cave with his team members around him but someone is missing and the crying sound made Gregor feels that something is wrong. His instinct was right, Thalia was dead and Hazard was crying hard with Thalia in his arms. Then there are some confusions and unanswered questions. Gregor leaves for regalia and the story of Gregor and the Marks of Secret ends with Gregor staring at the sword with fear in his eyes.
Gregor and the Marks of Secret became the New York Times Bestselling series and also the Book SENSE Bestselling Series. The writer Suzanne Collins left the end of the book Gregor and the Marks of Secret in suspense. This made the readers look forward for the next part of the novel that will precede Gregor and the Marks of Secret to find out if Gregor has to be a part of another interesting Prophecy or is the story of Bane to continue. The intense drama and high pace building in Collins writing has always amused the fans. The sizzling adventures and prophecy mysteries with a vivid ending in Gregor and the Marks of Secret is surely a good move to keep the readers panting for Suzanne Collins next installment.