Characters: Dumbledore, mystery guest
A/N: Crossover with Hellblazer, which will tell some of you who the guest is.
A Hogwarts alumnus had returned for assistance: a blond Muggle-born Londoner, direct and straight-speaking. He wasted no time in making his request.
"I need some Dreamless Sleep potion, Albus. As much as you can spare. This is driving me crazy, and Poppy's the only one I know who can help."
"Certainly, my boy. But I do not advise you to continue taking it for too long: dreamless sleep is not a healthy thing, when prolonged. And one more thing: what happened in Manchester was not your fault. You did all you possibly could to save the girl. Remember that, John."