The Tale of Despereaux is a Newberry Medal book by famed children's author Kate DiCamillo. Despereaux is the story of an unusual hero, a mouse. Despereaux was born with his eyes open and lives his life that way, looking for adventure and love in places other mice fear to go. For this reason, Despereaux finds himself trapped in the dungeon of a castle while the girl he loves is facing certain desolation at the hands of a disappointed rat and a forgotten child. Despereaux must save the day despite being less than two inches tall. The Tale of Despereaux is a funny yet eye opening novel of heroism that will both entertain and inspire its readers.

Despereaux is born the last child to a self-centered, French mother and her adoring husband. Despereaux is the only of his litter to survive, leaving his family convinced he will not survive infancy. This, coupled with the fact that his eyes are open from birth, make Despereaux an oddity among his siblings. Despereaux only adds to his oddness when he refuses to be frightened of the humans, to search for crumbs as his siblings do, and when he reveals himself to the king and Princess Pea in order to listen to music.

Despereaux's brother informs his father of this odd behavior. The music is the last straw for Despereaux's loyal mouse father. Lester calls the Mouse Council together and tells them of Despereaux's latest behavior. After hearing that Despereaux has revealed himself to a human, the council feels it has no choice but to condemn Despereaux to death in the dungeon.

In an odd ceremony, Despereaux has a red thread tied around his neck and is sent to the dungeon under escort. When he arrives, Despereaux finds the dungeon to be a dark, sad place. Despereaux meets Gregory, the dungeon keeper. Gregory takes Despereaux under his care, protecting him from the hundreds of rats living in the dungeon.

Roscuro is a rat who is fascinated by light. Most rats do not like the light, but Roscuro cannot get enough. One day Roscuro goes upstairs and finds himself in a dining room in the middle of a dinner party. Roscuro climbs to the chandelier to get a better view of the festivities. Princess Pea sees him up there and cries out, causing Roscuro to fall. Roscuro falls into the queen's soup bowl, causing her to die of shock. The death of the queen devastates the king, causing him to outlaw both rats and soup in the kingdom.

Miggery Sow is a servant girl who is brought to the castle after a soldier discovers a man claims to have bought her from her father. Miggery becomes a servant at the castle, but she is so lazy and easily distracted that she is a poor servant. Miggery wants to be a princess someday, so when Roscuro suggests they kidnap Princess Pea together, Miggery jumps at the chance.

Despereaux returns upstairs after Gregory sneaks him onto his dinner tray after a meal. When Despereaux hides in the kitchen pantry, he overhears the plan Roscuro has devised to lock Princess Pea in the dungeon. In love with Princess Pea, Despereaux tries to save her by telling the king where she is. However, the king does not believe Despereaux. It is then that Despereaux realizes he must save the princess himself.

Despereaux returns to the dungeon to save the princess, but loses his spool of thread that he planned to use to keep from getting lost. A rat offers to help Despereaux. The rat takes Despereaux to Princess Pea, but Roscuro does not intend to lose his prisoner. A fight begins. Roscuro smells soup on Despereaux's breath and is distracted. The princess promises to allow Roscuro to eat soup if he will allow her to go free.

Despereaux is hailed a hero and becomes Princess Pea's good friend. Roscuro is allowed to come into the light whenever he likes. Miggery Sow is reunited with her long lost father. Soup is returned to the menu of the kingdom.