As a child Turin was like his mother, Morwen, somber and quiet, but strong-willed. Turin's sister Urwen (Lalaith) dies at a young age due to a plague that swept through the region. While only 8 years old, his father Hurin went to fight in the Battle of Unnumbered Tears where he was captured by Morgoth and taken back to Angband. As a result of his unwillingness to reveal the location of Gondolin (the hidden elf city) to Morgoth, Hurin and his children are cursed and he is kept alive to watch the realization of his children's dooms.

When Hurin fails to return from the battle, Morwen send Turin off to live with the elves in Doriath in order to keep him safe. Thingol, the king there, adopts Turin as his own son. Morwen remains in Dor-Lomin because she is pregnant, and soon gives birth to a daughter, Nienor. Turin grew strong in Doriath, and soon went out to battle orcs at the front lines where he befriended an elf named Beleg. Upon returning to Doriath one time, he has an argument with an elf. Later, the elf attacks Turin, but he is bested and Turin forces him to run naked through the woods. While attempting to jump a ravine, the elf slips and dies. Turin, fearing what will happen to him and too proud to tell how the elf attacked him first, flees Doriath. Thingol, however, learns the whole story (from an elf who loved Turin and watched over him). Pardoning Turin, Thingol send Beleg after him to share the news of his pardon and welcome in Doriath.

At this time Turin joins a band of outlaws, and eventually becomes their leader, hoping to use them to raise a force to battle the orcs. He leads them out of Dor-Lomin and into the south where they find a petty-dwarf named Mim who provides them with shelter. After years of searching, Beleg eventually finds Turin and he joins him for a time. Mim, out of hatred for the elf, betrays their location to the orcs who attack and capture Turin. Beleg, wounded, follows soon after him. Finding an elf released from Angband, they free Turin from the orcs. Turin, however, waking suddenly in the dark and believing he is being assailed by orcs, strikes out and kills his friend Beleg. Grief striken, Turin is lead to Nargothrond by the freed elf.

In Nargothrond Turin rises again in stature, and falls in love with an elf-maiden named Finduilas over a period of five years. Morgoth, however, sends orcs and the dragon Glaurung to do battle against the elves. Glaurung succeeds in routing Nargothrond and his orcs capture many elves, including Finduilas. Glaurung lies to Turin, however, saying his family in Dor-Lomin is about to be murdered if he does not go there quickly. He does, but upon returning to his home, he learns that Morwen and Nienor had already gone to Doriath. Realizing the deception, he now sets off to find Finduilas. Unfortunately, the orcs had been waylaid in Brethil, and had killed all their captives. Thus Turin, believing Nienor and Morwen to be safe, settles in Brethil.

Morwen and Nienor, however, do not remain content in Doriath and so they set out with a group of elves to discover what happened in Nargothrond. Upon arriving, Glaurung causes the group to be separated and he finds Nienor. Dominated by his evil power, Nienor is rendered mute and she is guided back towards Doriath by an elf Mablung. Morwen, however, disappears and is not seen again. During the return trip, Nienor suddenly runs off, stripping her clothes and fleeing madly. Mablung is unable to catch her, and she eventually finds herself in Brethil, lying upon the grave of Finduilas. Turin finds her there, and brings her back to his home. Upon waking, she weeps and is unable to remember anything of her past so they name her Niniel, Maid of Tears.

Over time, Niniel and Turin fall in love and are married. Glaurung then leaves Nargothrond to come upon Brethil. Niniel is, at this time, now pregnant. Turin devises a scheme to hide in a ravine that Glaurung must cross to get to Brethil and kill him as he passes over. His plan works, but he is wounded by the dragon's blood and he faints. Niniel, unwilling to wait behind, follows to see the fate of Turin. She finds Turin fainted and assumes he is dead. The dragon wakes, and in his death throws, reveals to her the truth of her past. Her memories return and Nienor calls out to Turin: "Farewell, O twice beloved! [M]aster of doom by doom mastered! O happy to be dead!' She then throws herself into the ravine and dies.

Turin soon wakes, and learns of all that his happened. Distraught, he asks his sword if it will take his life, and it agrees to. Thus, Turin throws himself upon his sword and he dies as well. Having finally accomplished all he wished, Morgoth releases Hurin, who eventually comes upon the graves of his children. There, he spies a woman - his wife Morwen. She asks what happened to them, but Hurin will not tell her and she passes away in the night. The book closes with this scene of Hurin with his wife as she dies upon the grave site of her doomed children.