According to the mythological stories, Hercules was born of infidelity. Zeus impregnated a Grecian woman named Alcmene, and Hera was incredibly jealous. She sent two snakes into Hercules's crib, but he strangled them before they could bite him. Hera was hellbent on making Zeus pay.
Hercules did end up marrying Megara and having two children, but Hera sent a fit of madness to Hercules, and he ended up killing all of them. (Bleak.) Hercules surrendered himself to the will of the god Apollo in hopes of atoning for his crimes. Apollo forces him into 12 labors, which include killing the creature called Hydra and kidnapping Cerberus from the Underworld (we see you, Disney). After that, other adventures included rescuing the princess of Troy from a sea monster and helping Zeus defeat the Giants.
In the end, Hercules marries again. His wife, Deianeira, gives him a cloak covered in a balm given to her by a centaur. The centaur assures her it will make him love her forever, but it's actually a horrific poison that burn Hercules's skin. He can't get the cloak off, and instead begs his friends to build a funeral pyre. He throws himself on it to burn alive, and Hera finally relents, sending Athena to carry him from the pyre up to Mt. Olympus.