Following the suicide of their best friend, Ethan, high school sophomores Fox and Pete discover a mysterious cave system expanding from the site of his death, the chambers abloom with shapeshifting fragments of Ethan's memories. Racked by grief, the two friends explore the perilous mindscape in search of answers. For Fox, who shared a fledgling romance with Ethan, the quest becomes obsession, the expeditions more reckless, into deeper and wilder recesses where the most precious secrets are guarded by strange beasts.