Laura (Mylene Dizon) desperately needed money for her sick mother and was pushed to vend herself to Antonio (Allen Dizon). Their one night together gets Laura pregnant with the twins Kara and Sara (Julia Montes). Meanwhile, Laura’s devoted suitor Ishmael (Ariel Rivera), willingly takes on the responsibility and served as father to the twins as they grew up.
Their deprived but happy family life is shaken when at the age of 7, Kara is diagnosed with leukemia. Kara’s sickness takes its toll on the family and all the attention showered on Kara causes a rift between her and Sara. Laura has no recourse but to turn to her daughters’ biological father to give Kara a fighting chance to be cured of her illness.
Laura tells Antonio that they have a daughter and he gladly welcomes Kara since his wife Lucille is unable to bear him a child. Kara selflessly unburdens her loved ones by joining her new family, but promises she will return to them once she is cured.
Years pass and the twins are now 21 years old. Kara is healed of her leukemia after undergoing treatment in the U.S. but feels incomplete without the love of her original family. Meanwhile, Sara grows up ambitious, having had enough of her impoverished existence.
Unknown to their parents, Kara and Sara have a chance encounter. They realize how different they have become and how unhappy they are with what they have at the moment. They agree to trade places, seeing in each other an opportunity to find what’s missing in their lives.