"Hellcats" revolve around three women from different generations.40-year-old Kim Young-Mi (Lee Mi-Sook) is an interior designer and a single mother. She’s proudly independent and seems to enjoy her life and work. One day, she starts a new assignment working for a theatre company. A much younger actor (Yoon Hee-Seok) in the theatre company takes an interest in Young-Mi and they become involved in a romantic relationship. Young-Mi is then shocked to learn for her doctor that she is in the first stages of menopause. 27-year-old Ami (Kim Min-Hee) is Young-Mi’s younger sister. She has lived with Young-Mi for the past three years without paying rent. Ami struggles through life as an aspiring screenwriter. She’s on her 17th re-write for a screenplay that has been in the works for over a year. Her personal life isn’t much better. Ami’s boyfriend (Kim Heung-Soo) is an aspiring musician, but, like herself, doesn't make any money. After her 27th birthday, Ami decides to make a change and goes on a blind date with successful accountant Seung-Won (Kim Sung-Su). Lastly, there’s Young-Mi’s teenage daughter Kang-Ae (Ahn So-Hee). Kang-Ae’s had the same boyfriend (Kim Beom) for three years, but has yet to kiss. Kang-Ae tries to jump start their relationship by taking lessons from her best friend Mi-Ran (Kang Hae-In). Things become complicated when Kang-Ae starts developing feelings for her female friend Mi-Ran instead