After an incident which nearly cost Littlefoot's grandmother her life, Littlefoot learns a series of lessons which his species call "Wisdoms". Meanwhile, a trio of dim-witted Beipiaosauruses named Loofah, Doofah and Foobie arrive in the Great Valley and behave in a strange manner towards Littlefoot and the gang. Littlefoot is determined that they learn the "Wisdoms" and the journey to the one place the trio have dreamed of, Berry Valley, begins.

Based on the Korean legend, unknown creatures will return and devastate the planet. Reporter Ethan Kendrick is called in to investigate the matter, and he arrives at the conclusion that a girl, stricken with a mysterious illness, named Sarah is suppose to help him. The Imoogi makes its way to Los Angeles, wreaking havoc and destruction. With the entire city under arms, will Ethan and Sarah make it in time to save the people of Los Angeles?