The book has been translated in Danish, English, German, Russian, Greek, Estonian, French, Indonesian, Italian, Japanese, Norwegian, Polish, Portuguese, Czech, Swedish, Spanish and Catalan.

Unable to refuse a call for help, he breaks the tradition and goes outside, where the stranger, an old man, hands him a sealed letter and begs him to deliver it to a knight clad in black armor and a white shield residing in a nearby forest inn.

In the city of Dangria, the mayor, an agent and sympathizer to Eviellan, attempts to imprison the boys under false pretenses, but a diversion by Piak allows Tiuri to hide long enough to memorize the contents of the letter and destroy it.

When Tirui is brought before Sir Ardian, the local Toll Master, he attempts to bargain for his and Piak's release by offering Edwinem's ring as a deposit.

Upon recognizing the ring, and after learning about Edwinem's demise and that Tiuri carries an important message for the king, Sir Ardian promptly provides the two boys with an escort to the capital.

With his identity revealed, Iridian orders Tirillo to complete his mission to ask King Dagonaut for an alliance and Ewein to wait for Ristridin's return, before he departs the castle; shortly afterwards, the knights of Eviellan also leave.

Tiuri, Piak, Bendu and Ewein leave for Islan, an isolated fortress at the very edge of the Wild Wood, to ask its master, Sir Fitil, about Rsitridin's whereabouts.

While taking a rest in a village near the forest, they meet Red Quibo, the local town drunk, who tells them of a strange jousting he witnessed in the Unholy Hills, an area within the Wild Wood; a story which has been dismissed as his usual drunken fantasies.

They day after, they arrive at the castle, where Fitil and his beautiful daughter Isadoro tell them that Ristridin had indeed come to Islan during the winter, but left again in short order after reporting that the forest contains nothing of interest.

During a ride to the Wild Wood with Isadoro, Tirui briefly leaves Ardanwen and is surprised to find flowers weaved into the destrier's bridle upon his return.

He learns that Marius, along with his brothers, was forcibly drafted by strange men for work in the forest, but he managed to escape; upon seeing his friend Tiuri at Islan, he left the flowers as a signal to him.

At said place, Tiuri and Piak discover a message left by Ristridin telling that his entire retinue was slain by enemies hiding in the forest, with him being the only survivor.

Realizing that the stories of Ristridin's departure from the Wild Wood are fake and that Sir Fitil must be in cahoots with that enemy, Tiuri decides to leave the forest at once and spread this alarming information.

But when Piak briefly separates from his friends, Tiuri and Marius are captured by a band of Men in Green, soldiers from Islan, and Red Riders from Eviellan.

Tiuri beats Jaro, but refuses to kill him; then the Knight takes him and Marius to the Tarnburg, a ruined castle deep within the woods, and locks them into a secure room.

As they continue playing, the Black Knight freely divulges that his presence in the forest is the prelude to a massive two-pronged attack against Unauwen's realm from two sides - one from the south, the other from a long overgrown road and a forgotten mountain pass hidden by the Wild Wood.

From him, Tiuri and his companions learn that Tehalon only tolerates Eviellan's presence in the Wild Wood because he and his tribe are neutral towards the affairs of the outer world, and they hope that the Black Knight and his followers will leave them alone if left unmolested.

However, when the King of Eviellan personally approaches Tehalon to demand the surrender of the fugitives, the Master of the Wild Wood lies to him by claiming that the three will be sacrificed to the forest spirits.

Hounded by the soldiers of Islan, tired and feverish, he stumbles into the camp of Adelbart, a drifter and former member of the bandit gang which Ristridin has smashed.

After nursing Piak back to health, and after hearing his story, Adelbart escorts him to the Brown Monastery, where the abbot immediately sends messages to King Dagonaut and summons Sir Rafox.

Upon a slip of tongue on his part, Adelbart is made to reveal that he had once lived with the Men in Green for a time after his wanderings led him into their realm, and offers to act as an emissary for the group.

With Piak's escape, however, Sir Fitil has finally realized that his efforts to keep Eviellan's presence in the Wild Wood secret are futile, and he and Isadoro release the knight.

After the Black Knight had set the Wild Wood on fire to punish Tehalon for his aid to Tiuri, the Men in Green join the fight against Eviellan.

However, the Black Knight and a number of his followers escape into the Unholy Hills and engage in a guerilla war, striking at the outposts of civilization bordering the forest.

He also sends a force to destroy Islan; Sir Fitil dies defending his castle, but Isadoro continues the fight and succeeds in repelling the enemy.

After the conflict is thus concluded, Tiuri and Piak pay a visit to Menaures in the mountains and find him in the company of a young boy named Idian - Prince Iridian's son, who was sent to live with his granduncle to learn how to rule his future kingdom wisely.

The Guardian's Philip Womack wrote: "The book is beautifully constructed, and has passages of urgent writing that take their inspiration from fairytales as well as the Arthurian legend."

Irish Times journalist Eileen Battersby wrote: "This is a fast-moving, wonderful old-style adventure written in a solemn, deliberate and descriptive prose.