Frank Middleton is an 11-year-old science nerd who has trouble making friends. When the real world makes him feel scared or sad, he retreats to the Aurora Shell, a special hideout in his closet full of everything he loves. Then, one day, he discovers an empty space behind his favorite Big Bang Theory poster: a tunnel that leads to another dimension! There, he meets a boy called Andy, who becomes his first true friend. Frank begins to think that this other world might be a better place, but he soon realizes that it holds dangers he never could have imagined. And as much as Andy helps him to learn the true nature of friendship, Frank soon realizes that Andy might need his help even more.