You can find a summary and analysis of Homer's Odyssey right here at enotes. Just click on the links I've included and look for the information you need.
The Odyssey is the story of Odysseus's return home to Ithaca after the Trojan War. It was Odysseus who came up with the idea to build a huge, hollow wooden horse as a "gift" for the Trojans. Greek soldiers hid inside the horse, and when the Trojans were asleep, passed out from their drunken celebration of the apparent retreat of the Greeks, the hiding soldiers came out of the horse and opened the gates to the full Greek army. Troy was utterly defeated and destroyed.
I hope this helps you. Repost if you have a more specific question about the story.