A "doppelgangers" website has facilitated the connection between two complete strangers that look like identical twins. Law firm partner Ko Sau-shing tracks down his former lover Yu Fung, whom he has not contacted for ages, online, and Yu Fung is looking for a part-time boyfriend with a similar appearance to him. Sau-shing arbitrarily approaches applicant Mo Kei-nam, who is a dead ringer for him. The duo also covertly agree to swap identities for two weeks. Sau-shing plays the role of Yu Fung's "substitute lover", and deadbeat Kei-nam disguises himself as Sau-shing while simultaneously dealing with his wife Lee Chi-ying and father-in-law Lee Kwun-hang as each and every crisis at the law firm is handled by him. While the identity swapping deadline looms, this pair of lookalikes are eventually shocked to realize their mutual life trajectories are already different from their expectations.