Pobby and Dingan are Kellyanne Williamson's best friends, maybe her only friends, and only she can see them. Kellyanne's brother, Ashmol, can't see them and doesn't believe they exist anywhere but in Kellyanne's immature imagination. Only when Pobby and Dingan disappear and Kellyanne becomes heartsick over their loss does Ashmol realize that not only must he believe in Pobby and Dingan, he must convince others to believe in them, too.