The novel predominantly centers on two characters, cave diver Gyre Price and her handler, Em. Gyre has taken on the task of exploring a dangerous cave system that is partially underwater. It is also home to the Tunnelers, strange alien creatures capable of instantly killing any they come across. While she has some limited experience doing this job, Gyre has lied about her job history in order to secure the large paycheck that comes with spending weeks mapping out the cave while inside a specialized caving suit, unable to take it off or eat conventional food. During this she is watched by her handler Em, who is tasked with ensuring that Gyre remains safe and calm via the administration of drugs or other methods. Unbeknownst to Gyre, Em has secrets of her own, the first of which is that she is the only handler on site—a job typically handled by multiple people to avoid handler burnout and allow for sleep. (via https://en.wikipedia.org/wiki/The_Luminous_Dead)
