Eternity's Handmaiden

Alexis Locke gave the first forty years of her life to an agency that never thought twice about putting her in harm's way. After fifteen years of voluntary retirement and solitude, Alexis is asked to investigate the deaths of five seemingly unrelated scientists, one of whom happens to be the son she gave up at birth. As she follows the clues to her son's murderer, Alexis stumbles upon a plot that's as big as the galaxy and spans the future as well as the past. And then she finds out that she's the main player.