Yesterworld (Down World Series, Bk. 2)

In the sequel to Down World, Marina is lured back through the doors...

It's been almost two years since Marina O'Connell entered Down World in order to save her brother and change life as she once knew it. Now, she lives in a plane reality with her dad and stepmom, while her brother is with their mom in Oregon, far away but still alive.

As Marina sets out to complete her senior year as normally as possible, she catches the attention of the young new history teacher, Mr. Martel. But beneath his cool exterior, he's not who he seems. He needs Marina's help finding someone he lost in a place familiar to them both.

Marina swore off ever using the portals again, but beneath her ironclad resolve is an irresistible desire to revisit the world behind the doors. And so, she journeys into the door marked YESTERDAY to help find those that have been left behind. But one past turns into many, and as the limits of time travel stretch further and further out, Marina finds herself in a time and place she never expected to go and where getting back home may never again be an option.