He'd have done everything differently if he'd known she'd be gone so soon... When Lisa married Alex, she gave his life meaning. She was a professional astronomer: a stargazer. And when she gazed at Alex, she saw that behind his tough exterior was a man she could love. Alex, Lisa and their young son Connor made a happy little universe. But then Lisa dies in a train crash, and their universe is destroyed. Alex is shattered by loss, and overwhelmed by the difficulties of being a single father to a six-year-old boy. How can he and Connor carry on without Lisa lighting up their lives? Then Alex meets four strangers. Two men and two women, who never met Lisa, but whose lives changed profoundly because she died. As Alex hears their stories, he begins to realise the world may not be as cruel and senseless as it seems.