Petofi had already possessed the body of Quentin Collins so he could travel to 1969. Aristede lured Wanda to Petofi by promising her that he would treat her to champagne. Petofi used his powers to convince her to go through with the I Ching process. Wanda ended up throwing the wrong hexagram.
Quentin tried to stop her, but she was too far into the trance to be disturbed. When she went through the door, she saw a vision of a laughing skeleton. After seeing this, Wanda turned into a skeleton and died. Petofi forced Quentin to bury her.
Petofi finally learned the right hexagram from Charles Delaware Tate.