Kayla Thorne is the creative director of Thorne Interactive and the fiercest protector of Project Echo, a program she has spent seven years building. Erin Vale, meanwhile, is the daughter of the company’s late co-founder and a brilliant cybersecurity engineer. Because of a will, the two women—who can barely stand each other—are forced to become co-leads of Project Echo and even live under the same roof during a security lockdown. In real life, they clash constantly and trust each other even less. But neither realizes that every night, under the anonymous usernames Night Voyage and Island Breeze, they become the one person the other can truly confide in.
As their late-night conversations grow deeper, Kayla and Erin slowly fall for each other online, while their real-life relationship becomes increasingly charged with arguments, jealousy, near-confessions, and moments of instinctive protection. Then, on the night they finally agree to meet at an old lighthouse, the truth comes crashing down: the person each of them has fallen in love with online is the very same woman she considers her most infuriating rival in real life.