Five years ago, Evelyn went to prison in her younger sister's place. She gave birth in jail, only to be told her baby had died. After release, her rare blood type saves Alexander's son Leo by accident, and she is hired as the boy's nanny. Leo grows strangely attached to Evelyn, sensing she is his birth mother. Serena puts on an act as a loving mother, but Leo rejects her outright. Alexander, believing Evelyn is a convicted criminal, is biased against her and fires her on the spot. Still, Leo insists Evelyn is good and vows to prove she is his real mom. The truth finally emerges: Evelyn is not only Leo's mother but also the person who saved Alexander years ago. Wracked with regret, Alexander helps Evelyn defeat all villains, and the lovers reunite.
