Summerland by Elin Hilderbrand

The residents of Nantucket are stunned when teenager Penny Alistair crashes her boyfriend Jake's jeep, killing herself and putting her twin brother, Hobby, in a coma. The other two passengers in the car, Jake and Demeter, wearing seat belts, are able to walk away from the accident. What made Penny commit such an impulsive, destructive act? The survivors blame themselves. Zoe, the twins' mother, is devastated. Having raised Penny and Hobby on her own after their father passed away before they were born, she wonders if her leniency towards them is somewhat responsible. She also mourns her affair with Jake's dad, Jordan. Jordan (who still misses Zoe) and his wife, Ava, have moved to Ava's home country of Australia for a year after the accident in order to give Jake a new beginning--their marriage is hanging by a thread after of the death of their newborn son, Ernie, a few years ago. Summerland, told through the eyes of the parents and the children, has all the hallmarks of classic Hilderbrand: immediacy of well-developed characters that you care about, descriptions of island life, and a story that pulls at your heartstrings.