The story so far...
As a result of one tiny change, back when it all started, Lord Voldemort didn't try to kill baby Harry Potter. He adopted Harry, renamed him “Harry Marvolo,” and has experienced great good fortune ever since. Wizarding Britain fell before him; the legitimate government came under his hand, and he set himself up as the Lord Protector of the realm. Activating the ancient magic of the standing stones, he sealed the British Isles off from the rest of the world, and set to work exterminating, enchanting, or enslaving all the Muggles in his purview.
Harry lived the first ten years of his life ignorant that he had been adopted, and ever since has been piecing together information about his birth parents - as he fulfills the duties of the Lord Protector's only son and heir apparent. His childhood has been one of privilege and progress: the old Muggle buildings are slowly being razed and replaced with palatial wizarding structures; despite rationing (the British Isles are not exactly self-sufficient) Harry has never known want.
But life is not so lovely for everyone. Muggles and Muggle-born witches and wizards are held in work camps or used as personal servants for high-ranking purebloods. Even the majority of purebloods have found themselves lacking the luxuries they once found commonplace: coffee, chocolate, citrus, cotton. Transfigured goods can only carry one so far. Wizards and Muggles living outside of the British Isles view them very much like we view North Korea today: fanatical, dangerous, and unappealing to most sane people. Dumbledore has fled the scene, along with scads of other witches and wizards who disagreed with the Lord Protector's politics.
A resistance movement, the Order of the Phoenix, remains active, primarily in England and Wales. They have managed to carve out a small sanctuary for themselves in a place called Moddey Dhoo, and some of their double agents pretend to work within the Lord Protector's government: primarily Minerva McGonagall, who has taken the Dark Mark and is now headmistress of Hogwarts, and Arthur Weasley, who oversees the Muggle work camps. Others are active in Ireland and Scotland.
The year that Harry Marvolo began attending Hogwarts, the Lord Protector devised a system of magical journals, in order to better keep tabs on his subjects. Fortunately, the Order was able to crack the spells: they can use the journals to send messages to each other privately, ORDER ONLY. Shortly after, inspired by the Marauders' Map, Fred and George Weasley created their own method of private journal communication: people under the age of majority, in-the-know, can declare that I SOLEMNLY SWEAR I AM UP TO NO GOOD. Eventually, private messages between one or two people were added to the journal spells - but these messages may be monitored by the Lord Protector's servants and cannot be trusted to remain secret.
The story begins on September 1, Harry's first year at Hogwarts. We are currently playing the summer between years 3 and 4. If you aren't familiar with the Harry Potter books, you might want to read our Introduction for Non-Potterites as a cheat sheet. To get caught up to the current state of play, you can read our trimesterly recaps: Year One, Autumn; Year One, Spring; Year One, Summer; Year Two, Autumn; Year Two, Spring; Year Two, Summer; Year Three, Autumn; and Year Three, Spring. Then, read the weekly recaps of posts to get caught up to the current moment.