Please help looking for story

it is a Severus and Hermione pairing. Severus is on a death eater raid at the beginning and finds a toddler and a baby in one of the houses. He goes to Hermione in the middle of the night and asks her to marry him so he could keep them; she accepts. gives her a potion to drink so she could breastfeed the baby. Later in the story the grandparents try to take the toddler.