Someone else's shoes

Twelve-year-old Izzy's life just seems to get more and more complicated: she is upset by her father's new marriage, and a new baby on the way; she is expected to look out for her ten-year-old cousin, Oliver, who has moved in with her family since his mother committed suicide, because his father is depressed and having trouble coping; and now Ben, the rebellious sixteen-year-old son of Izzy's mother's boyfriend, is also living with them--but when Oliver's father disappears, the three children put aside their differences and set out to find him.