Joe Haldeman 
Guardian [EPUB ebook] 

Uprooted from her Southern home during the Civil War, Rosa Coleman settles in Philadelphia with a husband whose compassion quickly turns to cruelty. But when that cruelty is inflicted upon their only son, she picks up and flees with the boy across the uncivilized Western frontier – and into Alaska to start anew among the region’s gold fields.But even the harsh journey across America has not prepared Rosa for the infinite possibilities that await her. Something not of this world has approached her. It has revealed the universe’s secrets to her. And it will take her on an extraordinary odyssey as she discovers the role she must play in bringing peace to Earth…