Odysseus was the beloved king of Ithaca. When he wasn't busy ruling, he spent his time with his wife Penelope preparing for their baby boy, Telemachas, to be born.
Crossing the Threshold
The Greek war soon broke out after Telemachas birth. Soon enough Greek officials arrived to take men away for battle. This included Odysseus.
Mentor
Listen to me and I will guide you.
Of course, Odysseus did not want to go. In attempts to change fate and stay home in Ithaca, he pretended to go mad, but his efforts were not successful. 
Trials, allies and enemies
Finally, Odysseus departed from Ithaca and set off to serve his part in the war. He hoped that one day he'd return back to his homeland and family but had no clue the challenges he'd face.
I shall love you all until I die. Gods above please bring me home. 
While away, Odysseus became highly favored by Athena the war goddess. The war lasted 10 years before Odysseus suggested a giant wooden horse. This was the strategy that finally ended the war.
On Odysseus' journey through the war and on his way home, he encountered many challenges. This included Cyclops, Sirens, travelling to the Underworld and many more.