"Shadow and Claw" is the combination of the first two books in "The Book of the New Sun" series. The story is about Severian, a torturer, and his journey toward the city of Thrax to become an executioner. Severian has a larger destiny, although it is unknown to him.

The story is being told by Severian looking back on his life. He remembers everything in great detail. He began life as an apprentice in the torturer's guild where he happened to encounter the leader of the freedom fighters named Vodalus. Severian saves him from being killed, and Vodalus gives him a single coin. From this point on Severian tries to learn everything he can about Vodalus feeling that their destinies are intertwined.

Vodalus is a fugitive and his lover, Thea, has a sister who is taken captive and put in the torturer's guild. Severian falls in love with Thea's sister, Thecla, and takes pity on her and helps her to commit suicide. He is expelled from the guild and sent to Thrax to be the executioner. He starts his journey but is challenged to a duel along the way.

The duel is a trap that has been set up by a woman named Agia and her twin brother Agilus. Severian falls in love with Agia and wins the duel and kills her brother. Severian befriends a girl named Dorcas and they continue their journey with Severian holding a holy gem called the Claw of the Conciliator, which Agia had hidden in his bag. Dorcas and Severian get caught in a fight and are separated. Agia will try to kill Severian in the story but Severian will continue to care for her.

Severian continues to travel and soon meets up with Vodalus. Severian swears loyalty to Vodalus and journeys to the House of Absolute to carry a message for Vodalus and find Dorcas and his other friends. Once at the House of Absolute he delivers the message and Severian and Dorcas head on toward Thrax with the intent to return the Claw of the Conciliator to the holy priestesses that it belongs to. Severian encounters strange creatures along the way revealing his future and the truth that he will in fact become a ruler some day. The story ends with Dorcas, Severian and several others being in a trance trying to find information for Vodalus regarding the old earth. At this point Severian warns the reader that they may not want to read any further traveling with him since the road will be very difficult.