Tallahassee Mitford is a young archaeologist working in a museum when her cousin Jason, an FBI agent, asks for her assistance. An ivory box covered with ancient symbols has been found in an airport locker, and he asks her to examine it. Tallahassee recognizes some of the symbols and thinks the box is related to a recent archaeological discovery near Lake Chad in Africa. However, it is also radioactive, albeit at a low level that poses no immediate danger to the people handling it. Tallahassee and Jason are African-Americans, and her most recent assignment has been cataloging the items taken from the Lake Chad site. She is looking forward to next week, when she is to leave for Egypt to join an expedition to the Sudan. At her recommendation, they lock the box in a safe in her boss's office for further examination by experts at the museum.
When Tallahassee gets home that night, she receives a call from the museum asking her to come back. When she arrives, she learns that her boss's office has been ransacked. Thinking the perpetrator might have been looking for the combination to the safe to steal the box; they open the safe and remove it. Opening the box, they find an ankh, a key carried by Egyptian gods and goddesses. Then the electricity goes out, and the ankh begins to glow and levitate. It starts moving, and Tallahassee feels compelled to follow it. It eventually arrives at the rooms containing the Lake Chad items and stops at a rod taken from the site that is now glowing as well. The rod is locked in a glass case, and Tallahassee is compelled to try to break the case and remove it. The glass is too strong for her, so the Rod rises of its own accord and breaks itself out. She grabs hold of the rod while the ankh touches its head.
The next thing Tallahassee knows the sun is shining brightly, and it's hot. Next to her is a dead body, grasping the ankh in one hand and the rod in the other. The body was a woman, dressed in a thin, cotton robe, her hair is braided, and she wears an Egyptian style headband. When Tallahassee looks at her face, it is almost like looking in a mirror. The dead woman could be her identical twin, except that her skin is slightly darker. Then she sees another woman running toward her. She is clearly African and dressed like the dead one, except that she wears a lioness mask. She tries to talk to Tallahassee, but speaks a different language. The newcomer picks up the ankh and with gestures persuades Tallahassee to pick up the rod. They are joined by two more African woman dressed like the first, and they pick up the body. As they are walking away, Tallahassee recognizes the place. It is Meroe, an important archaeological site in the Sudan. She remembers that they worshipped a lion god named Apedemek, which explains the masks. However, how she has gotten halfway around the world in the blink of an eye, she has no idea.
They arrive at a large building, and they lead her into a room with bedrolls, food, water, and clothing. After drinking some water and eating some food, she exchanges her sweaty dress for one of the cotton robes and her high heels for sandals. The others also put makeup on her face to make it appear darker and give her a wig and headband, like the dead woman was wearing. Then she hears the sound of a landing aircraft, and three men come into the room. They wear a uniform that Tallahassee does not recognize and carry firearms unlike any she had ever seen. When they start to argue with the women, Tallahassee follows an intuition by raising the rod and points it in the direction of the men. They immediately perceive it as a threat, and two of the men flee. The third man carefully backs out of the room without taking his eyes off Tallahassee. The women follow the men outside to their aircraft, which is similar to a helicopter but again unlike any she has ever seen, and she does not recognize the insignia painted on its side. They board the craft and take off.
At this point, they finally get around to exchanging names. The leader of the women is Jayta, the other two are Makeda and Idia, and the dead woman is Ashake. Shortly afterward, another aircraft arrives, but it is piloted by women. They board the craft and fly west, leaving the desert. They land near a temple, and she is taken to a room. Jayta finally takes off her mask and communicates with Tallahassee telepathically. Tallahassee learns that she is in the 2,000 year old Empire of Amun on a parallel Earth. The political situation is that the current ruler is a female, but she has a younger brother Userkof whose wife Idieze is ambitious. They have allied with Khasti, a newcomer who was unknown ten years earlier and who has developed his own following. Somehow, he hid the rod and the ankh in Tallahassee's world. Ashake, the dead woman, was also of royal blood. She was a priestess, but was still next in line for the throne. Ashake used her mental powers to pull the artifacts along with Tallahassee back to this world, but died in the effort. Jayta asks Tallahassee to take Ashake's place during the current political crisis, and Tallahassee agrees.
The following day Tallahassee meets Jason's double, Herihor, who also happens to have been Ashake's cousin. However, it is a little more complicated, because prior to Ashake becoming a priestess, they were betrothed. Having learned of Ashake's death, Herihor is not friendly toward Tallahassee. Then the priestesses hook Tallahassee's head up to a device, and suddenly Tallahassee has Ashake's memories and knows how to speak the local language. She feels rather strange, having two lifetimes worth of memories. She also learns some history.
Later that day she has a visit from Princess Idieze, whom they suspect of plotting against the empress. Since it is late in the day, they invite her and her entourage to spend the night. They have dinner in the same room that night, although they follow the Egyptian custom of separate tables. After Tallahassee retires for the evening, an intruder enters her bedchamber and sprays some liquid in her face, which knocks her unconscious. When she awakes, she realizes she has been kidnapped and is in an aircraft, tied to a stretcher. When the craft lands, Tallahassee finds that she is a prisoner of Idieze, Userkof, and the mysterious Khasti.
This report prepared by Thomas R. Feller