The Kane Chronicles (3 Book Series)

From Book 1: Since their mother's death, Carter and Sadie have become near strangers. While Sadie has lived with her grandparents in London, her brother has traveled the world with their father, the brilliant Egyptologist, Dr. Julius Kane. One night, Dr. Kane brings the siblings together for a "research experiment" at the British Museum, where he hopes to set things right for his family. Instead, he unleashes the Egyptian god Set, who banishes him to oblivion and forces the children to flee for their lives. From the creator of the hit Percy Jackson series.