Pokemon Stones

The Pokemon Stones are magical objects that Lisa and her friends needed to collect at the very start of the Ultimate Story.

Ultimate Story: The Beginnings
The Pokemon Stones were introduced after Lisa and her group met with Ribbon on Ripple Star to retrieve the crystal. Ly then revealed that she needed to crystal to find the 10 magical stones. She presented them with the Mew stone and then revealed that the Cubone that Lisa had obtained from Professor Oak contained another of the stones, to which the crystal had retrieved. Aware that they needed to be done, Ribbon decided to leave with the group as she is the sole guardian of the crystal.

The Journey Through Kanto
The journey to find the stones officially began when Lisa and her group met Ash, who, like them, were late to meet with Professor Oak. After he introduced to Ash his Pokemon partner, Pikachu, it was revealed that not only did she know Lisa, but also contained another of the stones, which the crystal extracted from her.