On rainy days, Gargantua attends lectures and visits various guilds to see how artifacts are made, instead of wasting time.

Some shepherds guarding vineyards in Gargantua’s lands ask bakers from Lerne carrying fouaces (an airy flatbread) for some bread. The bakers refuse and insult the shepherds, hitting one of them. The shepherds attack the bakers and seize their bread.

When he learns of the incident, King Picrochole the Third of Lerne orders his soldiers to attack the shepherds of Utopia.

Picrochole’s soldiers start sacking towns in their path, not even sparing homes infected by the plague. When they reach Seuilly, Frere Jean des Entommeures has the abbey bolted from the inside and saunters out with a shaft from the cross, using it to kill the soldiers stealing the monastery’s grapes.

Meanwhile, King Picrochole invades La Roche-Clermault and captures the castle. A shepherd informs Grandgousier of the siege. Grandgousier wants to first try resolving the matter peaceably, and sends men to understand why Picrochole is sacking Utopia. He also informs Gargantua of the matter by letter.

Having received his father’s missive, which entreats him to return to defend his land, Gargantua immediately leaves for his home country.

Meanwhile, after dictating the letter to Ulrich Gallet, his Master of Petitions, Grandgousier sends him to warn Picrochole of their plans.

At Picrochole’s court, Gallet declaims that it is unfortunate Grandgousier’s good will toward Lerne has been met by unnecessary hostility. It is now best that Picrochole withdraw from Utopia peacefully. He will not face violence on his way out.

Picrochole has no response to Gallet, except to ask his men to pound Gallet to fouaces. Gallet returns to Grandgousier, who investigates the dispute. Grandgousier offers to replace the fouaces his men took from those of Picrochole, but Picrochole seizes the bread and refuses peace. Grandgousier’s council suggests a decisive war may be the quickest way out.

Picrochole’s councilors le Duc de Little Trash, Le Comte Spandassaino, and Captain Squit flatter him with flowery language to persuade him to himself march against Utopia. When the old man Echephron advises caution, Picrochole insults him.

On his way from Paris to Utopia, Gargantua reaches Parilly, where he learns that Picrochole is at nearby La Roche-Clermault. Ponocrates advises they meet le Sieude la Vauguyon, a family friend who can counsel them about the goings-on. Vauguyon offers them his full support.

Gymnaste, Gargantua’s companion and Vauguyon’s employee, take a measure of the battle and find the enemy looting and pillaging. Captain Tri-ffart of the enemy camp says Gymnaste can pass through if he gives up his horse.

Gymnaste announces he is the devil, scaring many of the enemy’s soldiers. He then performs equestrian tricks on his horse, scaring them further. As the enemy cower, thinking he is a fiend, Gymnaste gets off his horse and kills the soldiers swiftly before heading back to La Vauguyon.

After hearing Gymnaste’s report, Gargantua rushes into battle with a huge company. He uproots a large elder tree on his way and uses it to smash the enemy’s forts, defeating them.

Gargantua and his men return to the chateau of Grandgousier, and the entire city greets them with joy. It is said Gargamelle dies of happiness, but the narrator does not care if she did since he cannot be bothered about her or any other woman. Grandgousier is impressed to see Gargantua caught the enemy’s cannon balls in his hair and holds a huge feast to celebrate the victory.