On a flight to New York at the end of her first book tour, up-and-coming writer Agnes Oliver meets Jack Verity, the handsome filmmaker and ex-husband of Geia Stone, a famous actress turned wellness guru, whose popular lifestyle brand Goddess promotes controversial therapies and expensive beauty tools in the name of self-care and inner nourishment. Jack invites Agnes to a party in the Hamptons, where she meets Geia and finds herself welcomed into the guru's inner circle. That summer, Geia arranges for Agnes to attend the Goddess Summit, an exclusive wellness retreat held on a remote Greek island. There, Agnes observes many strange happenings she can't explain, as one by one the other guests seem to fall under the spell of their enchanting host. When Agnes begins to discover who Geia really is, she realizes it's up to her to protect the other women at the summit from an unexpected and unwelcome fate.