Kariya will hear footsteps just a second or two after his own, always stopping when he does. If he turns to look, no one will be there, but the footsteps will always resume.

Eventually, he'll feel someone clinging to his back. He will be frozen in place and unable to speak while a boy who sounds like Zo says "Shh, we're playing hide and seek."

At that moment, Ruana will leap out in front of him. Then she'll vanish, Kariya will be able to move again, and nothing out of the ordinary will be there.