In the 1940s, the world was in turmoil, and it was crucial to decipher the enemy's communication codes in a timely and accurate manner. Rong Jinzhen has shown amazing mathematical talent since her childhood, and because she solved the problems assigned by her math teacher, she was noticed by more people, and even walked into the door of code-breaking by mistake.

When a young man discovers a screw inside his grandfather’s urn, he uncovers a cremation mix-up involving three families. Determined to return his grandfather’s ashes to their rightful place, he embarks on a cross-border journey filled with mistrust, unexpected challenges, and the hope of bringing peace to the departed.