South City Love Story.

Shen Yugui accidentally took an aphrodisiac and slept with Fei Nancheng while saving him abroad. Upon returning to China, Fei Nancheng also came back to cancel his engagement, only to find that his fiancée was Shen Yugui. To reclaim her company, Shen asked Fei to agree to the engagement. Unaware of each other's identities, they missed several chances to recognize one another. Fortunately, the truth was finally revealed, clearing all misunderstandings and leading to a happy ending.