The Silmarillion by J. R. R. Tolkien is a story of creation. Ea, the World that Is, is created, and the Valar prepare the way for the Children of Iluvatar. Along the way, the Valar and the Children of Iluvatar battle evil in the form of Melkor in order to survive and maintain good in Ea. The Silmarillion parallels the Christian story of creation in many ways but still manages to introduce its own mythology of the creation of the world and humanity.

Iluvatar creates the Ainur and reveals his plan of Ea. Some of the Ainur descend to Ea as Valar in order to prepare for the coming of Elves and Men. Melkor tries to rule but is thwarted in his design by Manwe. Melkor destroys Arda, and the Valar relocate to Valinor. Aule creates Dwarves, but Iluvatar sentences them to sleep until the Elves awake. The Elves awake, and Orome leads the Eldar to Valinor. Melkor is imprisoned. Melian and Thingol fall in love and rule Doriath. Feanor is born and creates the Silmarils shortly after Melkor is released from prison. Melkor causes discord between the Valar and the Eldar before destroying the Two Trees of Valinor and stealing the Silmarils. Feanor and his sons swear an oath that no one can possess the Silmarils. The Noldor depart from Valinor, killing some of the Teleri, and return to Middle-earth. The Valar create the Sun and the Moon.

There are many battles between the Eldar and Melkor, and Melkor kills Feanor. Turgon builds Gondolin, Aredhel grows bored and leaves, falls in love with Eol and bears Maeglin. Aredhel and Maeglin return to Gondolin. Men awake and are befriended by the Elves. Beren falls in love with Luthien and marries her after completing the quest of the Silmaril. When Beren dies, Luthien forsakes her immortality in order to be with him. The Sons of Feanor assault Thingol for possessing a Silmaril. Thingol raises Turin, who is captured by Orcs, rescued and marries Nienor, his sister. Turin kills Glarung who reveals Turin's identity to Nienor who kills herself. Turin also commits suicide when learning the identity of his wife. Morgoth learns the approximate location of Gondolin when he releases Hurin. Thingol has Dwarves place the Silmaril in the Nauglamir, but the Dwarves kill Thingol and steal the Nauglamir. Beren retrieves the Nauglamir. Tuor takes Ulmo's message to Turgon, but Turgon ignores it due to Maeglin, who betrays Gondolin to Morgoth. Tuor and Idril escape, and their son, Earendil, sails to Valinor to ask the Valar for help against Morgoth. The Valar defeat Morgoth and imprison him in the Timeless Void.

The Dunedain dwell in Numenor but begin to turn from the Valar and the Elves. Sauron gains control over the Numenoreans. The Valar destroy Numenor when Ar-Pharanzar wages war against the Valar. Elendil escapes from the ruin of Numenor and returns to Middle-earth. Sauron attempts to control the Elves through the Rings of Power, causing war between Sauron and the Elves. Elendil and Gil-galad form the Last Alliance, but Sauron kills them and is banished from his body for a time. When Sauron regains power, the Istari Wizards, messengers from the Valar, appear to help Elves and Men. The Istari find the Ring, and Sauron wages war, ending the Third Age in battle. Eventually, Men usurp Middle-earth, and the Elves return to Valinor.