On the night of their seventh wedding anniversary, jewelry designer Qiao Wan discovers a number, 487, visible only to her on her husband Cheng Yu's wedding ring. An old silversmith tells her that when the ring's temperature reaches 49, he will forget he ever loved her. A surgery three years ago plunged their marriage into misunderstanding and coldness—one thought they were hated, the other thought they were forgotten. When the ring truly breaks 49, Cheng Yu forgets to love her, yet remembers everything about her. Facing a 100-day limit, Qiao Wan decides to step back into his world.