Each episode focuses on mainly synonyms and vocabulary, featuring an underlying theme illustrated with a wide range of keywords, but can occasionally focus on introducing children to different science and other learning concepts, such as the Spanish language through passing mentions, history, and astronomy.
When Carolina outdoes Tiffany on the science project, she organizes an expedition with TD, Truman, and Martha to gather "exotic" plants.
This season marked the introduction of guest stars, including Jennifer Garner in "Too Many Marthas," poet laureate Billy Collins in "Billy Collins Speaks," and astrophysicist Neil deGrasse Tyson in "Eyes on the Skies."
Additionally, Christina Crivici finished her role as Alice Boxwood, with Michelle Creber taking over the character.
Furthermore, Kenan Thompson makes a guest appearance in the episode titled "Stanley Saves the Day".