Tom Bailey is a successful and charming New York City ladies' man who enjoys his single life, indulging in casual flings and short-term relationships. His best friend since college, Hannah, is the one constant female presence in his life. As Hannah makes plans to travel to Scotland for work, Tom begins to realize he has stronger feelings for her than mere friendship. When Hannah returns from her trip, she surprises Tom with the news that she has gotten engaged to a wealthy and handsome Scotsman named Colin.

Tom is initially devastated but resolves to support Hannah by agreeing to be her “maid of honor.” This role puts him in an unexpected position, challenging his friendship and newfound feelings for Hannah, all while contending with his dislike for Colin. As the wedding preparations progress, Tom's feelings for Hannah deepen, and he struggles with whether to reveal them or risk losing her forever. Tom must navigate the complexities of love and friendship as he grapples with revealing his true emotions before it’s too late.