From Dark Horse:
Nathaniel Wingate Peaslee was once a respectable professor of political economy. Though he taught at Miskatonic University in Arkham, his temper was of a reasonable sort, not at all interested in the occult. That has changed. In 1908, standing in the lecture hall, Professor Peaslee saw his classroom suddenly twist into an uncanny, alien vista, and he collapsed unconscious. What awoke was not the Nathaniel Peaslee his colleagues knew. At least, not his mind. Now associating with strange people, and speaking oddly of time, distant lands, and concepts of existence, his travels and research disturbed those who knew him, including his friends, wife and even children. It was not until 1913 that Professor Peaslee came back to his right mind, with no memory of his strange sabbatical. His search for understanding of those five missing years leads him and readers on a journey across the globe to a place where a long-vanished race still casts their shadow out of time.