Go to 'Outside Thebes' which is the gate of Thebes, ASK GUARD ENTER
(*Note:If you do not yet have friendship ASK GATE YES, you are escorted inside, go north, ASK KING FRIENDSHIP, go west into the gym, ASK AUTOLYCUS WRESTLE, ASK AUTOLYCUS YES, he will easily overwhelm you, stand and repeat. Then return east - you are granted Theban favor! Now you can go south and west to the witches)
From 'Inside the Electran Gate' go west, ASK WITCH HELP, she tells you that Hera will send a serpent to kill Heracles that night.
Go south to Heracles and wait.
At around 2 am, a serpent will enter the room. Heracles will attack it.
Rescue Heracles if you have the skill, or kill the serpent fast.
Once it is dead go north, east, north to 'Outside the Megaron' and the King will thank you.
Credit: <a href="http://www.legenddb.com">legenddb</a>