his is a story about Hae-jung and her 3 younger half-sisters (Yu-jin, Yu-mi and Yu-sun).
Hae-jung (age 27), the oldest sister, is looked down upon by her step-mother (who is the mother of her half-sisters; the sisters all have the same father). Hae-jung is quiet and self-sacrificing by nature, and works as a nurse for her father, a famous doctor.
Yu-jin (age 25), the second sister, is blunt and demanding. She is a medical doctor finishing her residency at the university hospital.
Yu-mi (age 24), the third sister, becomes engaged to a rich guy, but loves another guy (Tae-suhk).
Yu-sun (age 19), the youngest daughter, is still in school and has a heart problem.
Young-hoon (age 27), was raised in the same household as the sisters since his mother and grandmother worked as maids for the Jung family. Young-hoon, also a doctor, likes Hae-jung, but is pursued by Yu-jin.