What is the main conflict in Little Bee: A Novel by Chris Cleave?

Little Bee is the second novel by writer Chris Cleave. In this novel, a young Nigerian woman is released from an immigration detention center where she has been held for two years after sneaking aboard a British tea ship. This woman, called Little Bee, makes her way to the home of Andrew and Sarah O'Rourke, the only people she knows in England. However, Andrew has recently committed suicide and Sarah is still reeling from the shock which is compounded by the sight of Little Bee, someone she had thought was dead. Little Bee is a tragic story of simple humanity that leaves the reader struck by the inevitability of life even as they learn what it means to be human.