Compass to Death

Cahill Soliven, five days in her comatose state, was killed by an unidentified person. Before the doctor arrived in her room, Crysteia Manzon was already in Cahill's body and fighting the urge of sleeping because of the wound. Surprised by what happened after remembering her death and burial a week ago, Crysteia wanted to seek for an answer. How is she alive? Who killed the owner's body?