Which door do you go through to save the world? David, Xander, and Toria King never know where the mysterious portals in their house will take them: past, present, or future. They have battled gladiators and the German army, dodged soldiers on both sides of the Civil War, and jumped from the sinking Titanic. They\'ve also seen the stark future that awaits if they can\'t do something to change it--a destroyed city filled with mutant creatures. And they\'ve still got to find a way to bring Mom back and keep Taksidian from getting them out of the house. The dangers are hitting them like a whirlwind . . . but the answers are becoming apparent as well.