All the Little Live Things by Wallace Stegner
Fiction suggested by JoAnn
From Amazon – Scarred by the senseless death of their son and baffled by the engulfing chaos of the 1960s, retirees Joe and Ruth have left the coast for a California retreat. And although their new home looks like Eden, it also has serpents: Jim Peck, a messianic exponent of drugs, yoga, and sex; and Marian Catlin, an attractive young woman whose otherworldly innocence is far more appealing—and far more dangerous.