Helen Russell owns and operates a florist shop in New York City. What she loves about her work is the love associated with many of her orders, especially now during the Valentine season. She hopes one day to have that sort of magical love, what she envisioned was like that of her now-deceased parents where they just knew they were meant for each other.
She thinks she found that love when her best friend since college, Henry Hart, invites her to a masquerade ball being held at the botanical gardens where he works as the chief botanist. At the ball, she meets a masked man with who she connects in that emotional, romantic sense. The problem ends up being is that by the time they abruptly part company at the end of the night, neither knows anything about the other, including the other's name.
The only clue that Helen has is the boutonniere he was wearing and accidentally dropped when he rushed off, one that was ordered from her shop using what is arguably the best rose she's ever hybridized, one that she is only calling the mystery rose until she names it and that Henry has encouraged her to enter into a prestigious flower competition.
Helen, Henry and the other shop staff--her maternal Aunt Carol, and new employee Beth--go on a quest to find Helen's mystery man to match the mystery rose. Through the process, Helen wants those magical signs to tell her that the risks she is taking will end up with this mystery man being her true love, but she might fight that the signs are a little more subtle and may point closer to home.