This is a drama about two Childhood friends meet again in their adulthood and find themselves making a bet on a “diet challenge”. The story focuses on their journey of searching for love and health. Kim Young Ho (So Ji Sub) is a personal trainer for Hollywood stars. Even though he comes from a wealthy family background, he suffered a devastating injury during his childhood days. Now, he overcomes his problems with patience and stubbornness. Meanwhile, Kang Joo Eun (Shin Min Ah) is 33-years-old lawyer. She has struggled to support her family. Now, she is overweight and challenge her-selves for a diet.