Season 1 of My Girl premiered on December 14, 2005.

When Seol Gongchan meets the lively and beautiful Joo Yoorin, he finds out that she has connections to his missing cousin, whom his grandfather has been searching for. He asks Yoorin to lie about being his long missing cousin until he can find his real cousin. She says yes, but soon their feelings for each other get in the way of their plans. Gongchan's cousin, Seo Jeongwoo falls for Yoorin while Gongchan's ex-girlfriend, Kim Sehyeon, a pro tennis player, tries to win him back. Will the two ever tell each other how they feel? Will Gongchan ever find his real cousin?