There's this bloke Odysseus (also known as Ulysses) who's been away at a war in Troy lasting ten year. On the way back to his home in Ithaca and to his loving wife Penelope, he gets shipwrecked, and has all kind of adventures, which mean he doesn't get back for another ten years.

When he gets back he find Penelope is being pestered by a bunch of suitors, who think he's dead, and they are are drinking her out of house and home. So he turns up in disguise, and kills them all, with the help of his son.

It doesn't really have a lot to do with the plot of Oh Brother Where Art Thou...