Big P takes a fall (and that's not all)

Can small b, the only lowercase letter in the uppercase school, find a way to save the day? When a rainstorm washes away the bridge in front of the school, the letters must warn the school bus to STOP before it reaches the raging river. But Big P has taken a fall! How can the alphabet spell "STOP" without P? Watch b stand up--and upside down--for himself! Ideal for STEAM curriculums, this entertaining alphabet adventure sparks imagination, curios...