I will try to be as clear and detailed as possible.
The basic background of the story is that Persephone goes above ground as she has done for thousands of years to visit her mother (Thus giving us Spring and Summer) but on this particular trip Demeter is nowhere to be found. Sephone searches for her high and low but can find no trace of her mother causing her heart to break and die.
Despite Hades' role as Lord of the Death there are a few things he can not sense like the death of another god. Months pass until it is time for him to retrieve his beloved from above ground. He finds her laying in a peaceful repose and thinks her sleeping yet finds her cold as ice. As the realization dawns on him that his one bit of light is forever gone. His mind breaks and he begins to destroy all around him.
Zeus seeing this tries to reason with Hades but he will hear none of it. Knowing he can not kill another god Zeus speaks with Eros and Hecate to find a way to bind the grief ridden god. The two come up with a spell to put in to sleep and within a dream where Persephone and him are together.
This plan goes well Hades falling into a sleep several thousand year sleep until just a faint trickle of magic causes him to stir,
Please pm if interested with your continuation!