Anna Cooper accidentally gains an "Immortality System," but every time she dies, it drains a huge amount of energy. Deeply in love with Reese Cox, she willingly takes fatal blows for him. Yet, because she can’t truly die, Cox becomes numb to her suffering. He grows increasingly cold, even asking her to die in place of his first love who has received a death threat. Heartbroken, Cooper agrees, concealing that this is her final life. Only when her life signs completely disappear does Cox finally understand the truth—and by then, his regret is too late.