Angel of mercy: Eighteen-year-old Heather travels as a volunteer to Africa, where she provides direly needed medical help in Kenya and Uganda and hopes to act as God's hands on Earth. Angel of hope: After her older sister Heather, enthusiastic about changing the world, returns from doing medical missionary work in Uganda, seventeen-year-old Amber feels ignored and confused about her own future and decides to go back to Africa in Heather's place.