Yours Truly

Isobel Hanley was born with a birthmark. It's different from what most are used to, in fact- it's more like a brand, or a tattoo. Isobel has never shown anyone the mark, knowing that if anyone who isn't supposed to see it sees, she'll be thrown into a world that is not her own.
And, as she lives the life of a normal person, Isobel finds she has it all. Good friends, she's gained the attention of the school's star football player Joe Benton, and she's just gotten accepted into the college she's always dreamed of going to.
When her and her friends celebrate, they end up accidentally opening a portal into the Other World.
At first, they think nothing of it- or, at least, until the team captain for the girl's basketball team dies and miraculously shows up in Isobel's room one night.