The bear brothers Briar and Bramble are always causing trouble for Vick, but their mischief comes to an abrupt halt when Vick decides to shrink them out of his life. In the midst of their scuffle, the shrinking device goes flying and the three of them are accidentally shrunk down to miniature size. With no other choice, the trio must find a way to reverse the effects and return to their normal sizes. However, their quest is hindered by Vick's father, who unknowingly takes the machine with him when he visits to apologize to his son. Determined to restore their size and reunite with their family, the three embark on an adventure through a marvelous world concealed beneath our feet.