One morning, Bear receives a notice in the mail that he's won a free mambo lesson by an instructor from the Ha-Cha-Cha Dancing School. As he gets ready for the arrival of this instructor, he finds that the kids of the Big Blue House are learning new things as well. Ojo pretends to be a teacher with Treelo and Bear as her students and later takes them on a field trip to the bathroom of the Big Blue House, where they observe the wild otters in their natural habitat, the bathtub. Tutter, meanwhile, struggles to read a book with numbers. Later, everyone gets a surprise when the mambo instructor turns out to be Tutter's Grandma Flutter. In the Shadow segment, Shadow's story is "One, Two, Buckle My Shoe" narrated by a doctor.