The Aeneid continues the story Homer begins in The Iliad.  The names of two important heroes are changed:

Odysseus becomes Ulysses
Heracles (or Herakles)  becomes Hercules

Brief synopsis of action:

Book 1: Aeneas is cast ashore at Carthage (a city sacred to Juno) following a storm.

Book 2: During dinner, Aeneas tells Dido of his escape from Troy.

Book 3: Aeneas retells the story of his wanderings and the death of Anchises.

Book 4: With Juno's help, Dido falls in love with Aeneas. Aeneas is fated to found the Roman empire, however, so Jupiter orders him to leave Carthage. Aeneas departs. Dido kills herself.

Book 5: Aeneas reaches Sicily, where he conducts funeral games for Anchises.

Book 6: Aeneas goes to see the Sibyl at Cumae to get access to the Underworld. He meets Anchises in the Underworld.

Book 7: Aeneas lands in Latium. Latinus promises Lavinia. Juno and Allecto stir up war. Catalogue of Italian heroes.

Book 8: Aeneas secures the help of Evander and the Etruscans. Story of Hercules and Cacus. Aeneas gets armor from Vulcan.

Book 9: Turnus attacks the Trojan camp. Nisus and Euryalus. The camp has difficulty defending itself.

Book 10: Council of gods. Tuscan catalogue. Turnus kills Pallas. Juno saves Turnus from Aeneas. Aeneas kills Mezentius.

Book 11: Burial of Pallas. Diomedes' refusal. During Council, Drances abuses Turnus. The Trojans attack the Greeks. Death of Camilla.

Book 12: Single combat is arranged, but treachery provokes a general engagement. Trojans attack the city. In single combat, Aeneas kills Turnus.