Following a failed engagement, aspiring author Louisa "Lou" Klaussner (Chloë Grace Moretz) falls into a side hustle writing wedding vows for other people. Just as the charming serial dater Dash (Anthony Ramos) starts to show interest in Lou, she reconnects with her college best friend and long-time crush Warren (Manny Jacinto). She is shocked to learn that Warren is the fiancé of Olivia (Isabel May), one of Lou's wedding vow clients… putting Lou in the middle of a complicated love-rectangle.