Psyche wished all her young life for the perfect husband. And when she finds him, he's not just perfect, he's divine: Eros, the god of love himself. Unfortunately, with a divine husband comes a divine mother-in-law, and Aphrodite is not pleased that an "upstart mortal" dared to marry her son. To keep the two apart, Aphrodite locks Eros on Mount Olympus, and sets a series of tasks to wane Psyche's love. Now, if she ever wishes to see her husband again, Psyche must scale mountains, collect the deathly waters of the river Styx, and even visit the Underworld itself.
What's missing is the element of conflict. Is Aphrodite activiely opposing our gal Psyche? What you have here is a list of tasks, but no sense of who's trying to stop her. I can hear you saying "but but..the tasks, they're really impossible", and that is true. However, this is a novel, a romance novel (sort of) so we assume dear Psyche will prevail. What makes it fun is seeing the obstacles and how she overcomes them.
As to the difficutly, Miss Snark visits the Underworld often. It's called the luggage room.
Use the hook format to get an idea of the things you need to cover. Then make it your own.