London, 1946. Charismatic and free-spirited writer Juliet (Lily James) receives a letter from a member of a mysterious literary club founded in Guernsey during Nazi occupation. Her curiosity piqued, Juliet decides to visit the island. There she meets the delightfully eccentric members of the Guernsey Literary and Potato Peel Pie Society, including Dawsey, the rugged and intriguing farmer who wrote her the letter. As she learns about their wartime experiences and secrets, Juliet develops a life-changing bond with the book club and the island.