In "Be Careful With My Heart," the main character, Maya, is forced to give up her dream of becoming a flight attendant in order to move overseas and work, sending money back home to help her struggling family. She finds herself alone and with no job after being swindled by the woman who was supposed to employ her.
Maya is offered a job as a nanny and housekeeper by a wealthy widower named Richard Lim after Maya helps his youngest daughter, Abby, during an incident at the airport. In exchange for her work, Lim, whose business is in aircraft maintenance, offers Maya an educational scholarship. It doesn't take Maya long to discover that the family is suffering greatly due to the death of Mrs. Lim.
The children Abbey, Nikki and Luke show their distress in different ways as they try and cope with their mother's death. Abby, the youngest, is the most deeply affected, suffers from selective mutism and becomes overly sensitive to arguments within the family. Richard opts to have her homeschooled due to her condition, and she has gone through several nannies prior to Maya's arrival.
Maya becomes determined to win each child over and help the group become a happy family again. Over time, she does make each family member happy, including Richard. As the show progresses, Richard and Maya marry and have the twins Sunshine and Sky.