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 "Glaucus and Scylla" 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.
Once a simple fisherman, Glaucus is transformed into an immortal merman, a sea god with powers of prophecy. The ordinary world for him is swimming around, telling people they're futures, and being all godly and stuff.
Call To Adventure
When Glaucus sees the beautiful sea nymph, Scylla, walking naked on a beach, however, his watery world comes to a boil.
Refusal Of The Call
Unlike in some hero's journeys, Glaucus doesn't refuse the call at all. He swims right up to Scylla and tries to put the moves on her. Unfortunately for him, Scylla is not into mermen, and it's she who refuses the cat-call.
Meeting The Mentor
Determined to be with Scylla, Glaucus swims to the sea witch, Circe, to get a love potion. Circe isn't your typical mentor, however. Instead of helping him in his quest to claim Scylla, the sea witch tries to claim Glaucus for herself.
Crossing The Threshold
When Glaucus refuses Circe, she pretends to give him the love potion he requested, and the sea god swims off to pour the potion in a pool where Scylla likes to bathe.
Tests, Allies, Enemies
Is Circe really a friend? Will Scylla be his? (Really, this section is kind of spread out over the other steps in the journey.)
Approach To The Inmost Cave
As Glaucus swims toward Scylla's pool, his heart is beating fast. He wants so badly for the love potion to work.
Yeah, there's a pretty big ordeal here, but Glaucus isn't the one who goes through it. After he pours the potion in the pool, Scylla gets in and suffers a horrible transformation. Instead of making Scylla fall in love, Circe's potion causes a pack of vicious dogs to grow from her lower body. (Looks like Circe wasn't a friend at all.)
There's no reward here. Glaucus really botched this one.
The Road Back
Glaucus returns to his watery home, but not in victory.
In this part, the hero usually almost dies, but emerges victorious. This just doesn't happen in this story, though. Glaucus has already left the scene. The only sort of resurrection we can see happens to Scylla, who emerges from her horrible experience to live life as an awful monster.
Return With The Elixir
Glaucus doesn't succeed in his quest of love, so this part doesn't really apply. The only bit of new knowledge he has to go forward with, is that he should never ever trust a sea witch.