1930, Shanghai Beach.
Shen Du, a female detective in the French Concession, received a mysterious case: the deceased was smiling and had a dead flower that had been dead for fifty years in his ear.
There is no murderer, just a brass bell, and the bell rings on time at three o'clock in the morning.
She doesn't believe in ghosts and gods, only evidence. Until the moment she touched the dead flower, her fingertips ignited fire.
Antique dealer Xie Wujiu told her: This is not murder, but cause and effect. The debts incurred three hundred years ago must be repaid in this life.
Shen Duyin thought he was talking nonsense - until she discovered that the price of each peek into the truth was the loss of a memory.
Until she discovered that the man who was always smiling had an old scar on his left wrist that had blocked her too many times.
Until she discovers that all the clues point to her mother who has been missing for fifteen years.
"You owe me a life. From a previous life."
"Then I will pay it back in my life."
"My hand remembers you. It doesn't want to let go."
