Uncle Jake has a big surprise <P> for Henry and Henry's big <P> dog, Mudge. He's going to <P> build them a tree house! <P> At first Henry is all excited. <P> But then he remembers. <P> Mudge does not know how <P> to climb a tree. <P> How will Henry and Mudge <P> share a tree house if Mudge <P> can't climb?