He matches on a dating app and announces, within minutes, that he has built a working time machine. He is not joking, and he is not after a date — he needs a research companion to help him chase a creature guarding a book that records everyone's death date. Twenty-four chapters of dinosaurs, a Greek labyrinth, the night Vesuvius erupts, a Wild West bank robbery, and the reveal that the sweetheart he keeps mentioning is not waiting at home.