The Hero's Journey is a framework that scholar Joseph Campbell came up with that many myths and stories follow. Many storytellers and story-readers find it a useful way to look at tale. (That's actually putting it lightly. Some people are straight-up obsessed.) Chris Vogler adapted Campbell's 17 stages of a hero's journey, which many screenwriters use while making movies. Vogler condensed Campbell's 17 stages down to 12, which is what we're using. Check out a general explanation of the 12 stages.
The story of the Calydonian Boar Hunt doesn't fit perfectly into the Hero's Journey structure, but we're giving it a shot. As the gross old saying goes, there's more than one way to skin a cat.
Meleager, Prince of Calydon, is busy being an awesome, invincible hero. Life is good.
Call To Adventure
When his father, King Oineus, forgets to make a sacrifice to Artemis, the goddess sends a giant boar to ravage the land. Meleager's dad calls on him and a bunch of other heroes to slay the beast. Among the many heroes that show up is Atalanta, the huntress. When Meleager sees her, he feels a call of a different kind.
Refusal Of The Call
There's no refusal at all. Meleager jumps right on it.
Meeting The Mentor
Oineus is the closest thing to a mentor in this story, because he's the one who assigns Meleager the task.
Crossing The Threshold
Meleager and the rest of the hunting party set off into the wilderness to skewer that boar.
Tests, Allies, Enemies
Although everybody in Meleager's hunting party is allied against the boar, there's dissension in the ranks about Atalanta coming along. Meleager's uncles in particular don't want a girl along, but Meleager tells them to pipe down.
Approach To The Inmost Cave
Tensions are high in the hunting party as they head deeper into the boar's mountainous stomping grounds.
The hunting party comes face-to-tusk with the vicious boar. Many are wounded and some die, but Atalanta manages to draw first blood. In the end, Meleager slays the beast.
Rather than taking the reward of the boars hide himself, Meleager gives it to Atalanta. His uncles get all mad about this and try to take it from the huntress, but Meleager kills them. You could see this confrontation as an extension of the Ordeal.
The Road Back
Together the hunting party heads back to Calydon.
Instead of facing his greatest challenge and emerging triumphantly, Meleager is killed by his mother, Althea, who goes into a rage when she finds out he killed her brothers.
Return With The Elixir
No elixir here. Our hero is dead as a doornail.