Michael and Sofia are about to get a divorce. To prevent her husband from seeing their son Leah, Sofia deliberately hides the child. Michael assumes the child is being properly taken care of, unaware that Sofia leaves her weak and sick young son alone in a sauna so she can go out on dates with her boyfriend.
The sauna's temperature keeps rising and the oxygen runs out. Trapped, Leah calls and leaves messages for his mother many times for help, but Sofia completely ignores them. In desperation, Leah calls his father. Michael rushes to find him but is repeatedly deceived and blocked by Sofia, his mother-in-law Mary, and his sister-in-law Anna. They lie about the location multiple times, deliberately delaying rescue.
After a long struggle, Michael finally finds the villa and pries open the sauna door, only to discover that Leah has already died from heatstroke and suffocation. In her grief, Sofia learns that her boyfriend's son urgently needs a cornea transplant and, without hesitation, offers to donate the deceased’s corneas—not realizing the donor is her own son.
It isn’t until a company IPO press event that Sofia learns the harsh truth. She recalls the locked sauna door and the malfunctioning temperature control, finally realizing that her coldness and negligence caused her son's death and that Leah's corneas were transplanted to a stranger. The truth devastates her, leading to complete breakdown and lifelong regret.
