When two women plot to end an abusive marriage through murder, an unexpected visitor arrives — threatening to shatter everything they've carefully planned.

An unfathomable incident introduces a genius engineer to dangerous secrets of the world — and to a woman from the future who's come looking for him.

Fifteen years after losing Kang Ji-hoon, Jae-woo wakes in 2007 with a chance to fix the past—if he can reach the boy who no longer knows him.