The plot was essentially ripped-off from the fourth movie - Serebii is in a dangerous situation, teleports itself to another time, is weak from using too much energy, Satoshi-tachi nurse it back to health, it's stolen, then saved, and goes back to whenever it was in the first place. Not very original.
Hey, at least it didn't have a temporary death this time...BTW, was there any 4th movie music used?