Jung Hae-jung is the eldest of four sisters, and is kind and giving to her younger sisters - even though she's actually their half-sister. In contrast, second sister Yu-jin is ambitious and straightforward, and cares deeply for family friend Young-hoon. Third sister Yu-mi is materialistic, and gets engaged to a rich man, despite being more compatible with her ex-boyfriend Tae-suk. And fourth sister Yoo-sun is a high school student with heart problems and has a crush on her teacher. Each sister struggles to find true love, and conflicts and difficulties arise. But through it all, they remain true to each other.