Between the Veil and the Gate

Harry Potter jumps through the Veil to follow Sirius.
He doesn't land in the afterlife, but in Hawkins, Indiana- right in the middle of Stranger Things Season 2.

Deep beneath the town, Hawkins Lab is fighting monsters from another world.
Harry is convinced he's ended up in a particularly poorly managed department of the Ministry.
And because he is, unfortunately, Harry Potter, deciding not to help is never an option.

Armed with magic, sarcasm, and a surprisingly strong opinion on safety regulations and oversight, Harry inevitably becomes entangled in the lives of Hopper, Joyce, and a group of kids who are far too used to the impossible. Along the way, he also finds himself keeping an eye on Steve Harrington - something he insists he doesn't mind doing at all.

What starts as an attempt to "just help out" slowly alters the course of events in Hawkins- sometimes for the better, sometimes with consequences no one could have anticipated.

Because monsters are one thing.
But a British wizard who thinks your town fails to meet even the most basic safety standards?
That's a whole different kind of danger.