After Dementors attack Harry and Dudley, Vernon decides he's had enough of magic and enough of Harry. Nearly killed by his uncle, Harry unconsciously uses magic to call for help and is subsequently expelled from Hogwarts. Ending up in the care of Severus Snape, Harry finds himself brought on the professor's dangerous summer travels where they learn about Voldemort's past, Harry discovers he has an incredible rare magic, and they get to really know each other, so much so that Harry returns to Hogwarts as Snape's apprentice. With such a change in their relationship, the year at Hogwarts becomes an exercise in trust.