BJ, Baby Bop and Riff want to have fun with the alphabet blocks but are not sure what to play. Just then Megan's dog, Gracie, picks up the D block. Barney tells everybody she is very clever, because D is for Dog! Barney suggests that they all think of an animal for each letter of the alphabet, everyone is excited to give it a try. With a song and a dance they soon find animals for most of the alphabet but will BJ be able to find animals for the letters X, Y and Z...?