Your heroine’s apartment building is on fire. She’s helping people get out when she hears the cries of a baby. She finds the baby, rescues it, and flees the building. A firefighter assumes the baby is hers. What happens?
Does she hand over the baby or does she hold onto it until she can find the mom?
Who is the hero and how does he enter the story? Is he the firefighter? Is he the baby daddy? Is he the doc in the hospital who tends to your heroine?
Remember that this doesn’t have to be contemporary. The story could take place in any country, in any decade, and the heroine could have paranormal powers. There are so many directions to take this idea. Have fun with it.