Barney's excited to find out that Rusty's family is adopting a new baby girl from China; however, Rusty feels differently. He's not sure if he's going to be a good brother, and he doesn't know much about China. Barney takes him, BJ and Baby Bop on an adventure to China where he can learn more about his new sister's heritage. By the time he returns to the park, Rusty excitedly meets his new baby sister and realizes he will be the best big brother ever!