When a teenager reveals that she is gay to her devout Mormon parents, they decide to send her to a conversion therapy home in Utah.

Echo must deal with the regular dramas of high school, in addition to grappling with the murder of her older sister, Zoë. But when Echo receives a diary from Zoë’s boyfriend, she begins to untangle the secret life her sister lived.

Four friends on their way to Coachella stop off in Los Angeles to tour true-crime occult sites, only to encounter a mysterious young runaway who puts them on a terrifying path to ultimate horror.