Cyril Gordon, a young, well-educated agent with the Secret Service, is sent on a dangerous mission to retrieve a coded message from powerful criminals in a New York City crime syndicate. He manages to obtain the message, but his merciless adversaries are hard on his heels. If he does not evade them, they will not only retrieve the message, which will have grave consequences for the United States, but they will also undoubtedly murder him. Thinking only of escape, Cyril jumps into a waiting vehicle outside a neighboring building, closes the door and puts on a disguise. He finds himself rushed into a crowded church and up the aisle to the altar, where he believes he is being mistaken for the best man in a wedding. His mind is almost entirely taken up with the need to escape and, being inexperienced in weddings, is married to an ill, despondent, beautiful young woman before he knows what has happened. They are whisked to a packed reception at the bride's family mansion. There is no opportunity to come clean with the bride or her family before he and his bride are sneaked out of the mansion to catch the train for their wedding trip. The story which follows details their hair-raising adventures, Cyril's and Celia's rapidly growing respect and attachment for one another, and Cyril's need to get his message to Washington and then to spill the beans to his bride. Meanwhile Celia also has explaining to do: Why had she been marrying a man she had not seen for ten years and whom she abhorred?
This is a classic Grace Livingston Hill story. It is intricately and adeptly plotted. It has the charms and limitations of a well-written romantic melodrama of its time, the late Victorian era.