Draco Malfoy and the Sleep of Fleeting Death

Draco Malfoy: Proud, sophisticated pureblood, wizard, and potioneer; survivor of the War, ex-death-eater, sole heir to the Malfoy legacy, and sufferer of nightmares.
He's tired of the nightmares that plague him; so he begins to create a potion to stop them.
This is all very simple. So how in the name of Merlin did Potter get involved?

The story is mine; credit for the characters and settings goes to JK Rowling.