Deep Time follows the adventures of Lauren, a young woman from the East coast who falls in love with the West during a life-changing raft trip through the Grand Canyon. She begins graduate studies in the 1970s male-dominated field of geology, where she thrives on the explorations her classes afford her—studying undersea volcanoes, shepherding clueless undergraduates in a remote national park, and climbing canyons in Oregon to collect rock samples. But at home, things are deteriorating. After separating from her straying husband, she becomes best friends with Chris, an honorable male colleague who helps her fend off a predatory professor.