In 1943 during World War II, the daughter of a viscount named Lily Baines works as a wren in Withernsea, England. Her job is to listen in on German radio signals and decode them for the Allied Forces. Things are looking bleak for Lily as she is locked in a cold dark room to do her duty to her country as her father told her to do. She is proud to earn her honorable title as the daughter of a viscount, but the stresses of war exhaust her. She often thinks of her days as a debutante and all of her friends and lovers who are elsewhere working toward the war effort. She thinks of her male cousins and the boys that she danced with and how they could all die in this war. One day she is listening in on the radio and is surprised to pick up the sound of Americans communicating. She is confused by their conversation as she shouldn’t be able to hear the American forces. Her superior officer, Fiddian tells her to ignore it but she can’t help but listen anyway. She hears them talking about a conflict, then she hears them come under attack and start to sink. She hears one officer, ST1, continue to communicate over the radio as he and his ship mates sink and die in the attack. She is horrified by the sounds of their deaths and confused about the date that they mentioned- the ninth of March in the year 2023. She tells Fiddian, but she writes it off as a prank. Lily is haunted by what she heard and can’t let it go, and despite herself believes that she can do something to stop what she heard happen to ST1 and his crew. She calls her uncle who has a telegram and delivery service and asks him to save a letter to send to someone for March 9, 2023 to the hotel address that she also heard ST1 mention. On march 9, 2023, a navy man from Texas named Matt is checking into his hotel room in York, England, and receives a message and a case with a radio. He reads the letter from Lily Baines asking him to tune into her radio frequency at noon, and thinks it's a prank from one of his friends. But he tunes in anyway at the time, and is connected with Lily, who is surprised and excited that she was able to connect with him. Matt absolutely doesn’t believe Lily when she explains that she is “Lily Baines, petty officer in the Women’s Royal Naval Service.” Lily doesn’t try to convince him, just lets him know that she’ll be on the same frequency at the same time the next day, and that he can tell her when the USNS _Invincible _goes missing, which she knew would happen as she heard him talk about it on the radio before. Matt is shocked and confused but Lily is gone. He later sees on the news that the _Invincible _did go missing, and he tunes in to hear Lily again. While Matt is skeptical, Lily is able to convince him that she did in fact hear him- officer ST1- die from an attack over the radio frequencies. Matt can’t tell anyone, as obviously no one would believe that he is hearing someone from the past telling him these things. They devise a plan to meet daily over the radio, and Lily gives him information and coaches him through ways he can avoid the future she heard from coming to pass. Eventually, the date of the attack came, and Matt had to leave the radio and stop communicating with Lily. She is left to anxiously wait and hope that she hears his voice again. Three months later, she hears his voice and is overjoyed. He explains how he was able to avoid disaster with the information she gave him, and sincerely thanks her for saving his life and the life of his crew. They had grown close, and were aware of how unlikely and mysterious their meeting was, and how their connection through time could fizzle away at any moment. So they talk to each other, enjoying their conversation until their communication goes out. Before it does, they tell each other that they’ll always remember what happened between them. Matt is able to find Lily’s gravestone; she passed away in 2015. He feels a strange but intense sense of loss. He buys a veteran’s brick for her that says “Lily Baines, 2023 My signal moon.”