Hamilton Hill meets Estelle Redding in an umbrella repair shop and rescues her from two thugs soon afterwards. Estelle has hidden in the handle of her grey parasol the formula for "Coalex," an inexpensive substitute for coal which the coal trust is trying to prevent from reaching the market. Edward Burnham, one of the thugs, tells Hamilton that Estelle is a German agent, but the infatuated young bachelor fails to believe the story. Estelle entrusts Hamilton with the parasol, but when Burnham, who is revealed as Estelle's brother, finally snatches it away from him, they discover that the formula has been removed and that she has outwitted them all. Two German agents, posing as representatives of the United States government, nearly obtain the formula from her, but Hamilton, accompanied by Burnham, who has experienced a change of heart, rescue her in time. With the formula safely delivered to U.S. government officials, Hamilton and Estelle turn to more romantic pursuits.