Ishmael

Thrown back to 1867 Seattle with no memory of who he is, Spock is taken in by a settler named Aaron Stemple, who passes his strange houseguest off as a nephew called Ishmael. Piecing together fragments of a Klingon plot to alter Earth's history by killing Stemple before he can stop a 19th-century alien incursion, Spock has to solve his own mystery from the inside — in a town that, unbeknownst to him, may already run through his mother's family tree.