Marina is adopted. She's always known this - but the circumstances of her birth remain a mystery. Baby Blue, the newspapers nicknamed her at the time, after she'd been found wrapped in a blue shawl, in the hallway of a large, shared house in London. 24 Harrington Gardens. That was the house. And it's still standing now Marina is an adult; still split into flats. And one of them is to let. Of course, Marina knows that the chances of her uncovering the truth about her birth are remote - but she hopes the house might hold some clues. What if it's not just the house, though? What if someone connected to it knows what really happened that day? Someone who doesn't want the truth to come to light?