A woman walks her dog, Bob, along the shore of the Reach, an estuary where the river meets the sea. At a distance, she observes the old Tide Mill silhouetted against the sky. When Bob begins to bark, she runs after him and is shocked to see what Bob pulls out of the mud.

Chapter 1 begins the section, “Rule One: Tell a Lie,” and introduces the novel’s protagonist, the first-person narrator, Isa Wilde. One morning, as Isa lays awake in bed next to her partner, Owen, she receives a text that simply reads “I need you” (3). Isa knows immediately the message is from her school friend Kate Atagon, and knows that her other two friends, Fatima and Thea will have received the same text. Fatima lives with Ali and has two school-aged children. Thea works in a casino. Isa knows that she, Fatima, and Thea will answer as they always have when they receive that message: “I’m coming” (5).

The next morning, Isa lies to Owen to explain being up so early, and mentally practices additional lies she will need to tell him about her plans to visit Kate.