Homecoming by Kate Morton

 In 1959 in southern Australia, a man came upon an entire family dead while on a picnic--with the family's baby daughter missing.The deaths sent shockwaves throughout the community as people wondered whether there was a killer among them. Eventually the cops decided the mother had killed herself and her children. In 2018, Jess (a writer living in London) gets a call that her beloved grandma, Nora, has fallen and is in the hospital. She rushes off to Australia and while there, hears about the deaths in the 1950s--and that her grandmother was close to the family. Her grandmother had indeed been staying with the family that died but was extremely pregnant so hadn't gone on the picnic that day. She insisted that her friend Isabel would not have killed her children. Eventually we find out what really happened that fateful day, which involved a lot of twists and turns. My view of several main characters in the story certainly evolved as we learned more and more details about the events in the past.