Etta Spencer, having traveled miles and years from her home and been robbed of a powerful object that can save her mother, finds the renegade travelers who stole the artifact, but is torn when she realizes their leader is her father. Meanwhile, Nicholas, in Etta's natural time, asks Sophia Ironwood to help him track Etta and realizes the fight over the astrolab is not their only concern because an ancient power threatens to ruin the timeline altogether.