It's Christmas Eve and Isabel is counting the minutes until the store where she works closes. And then Marina walks in. A last-minute customer, one of those who are also indecisive and do not allow themselves to be helped. Fed up with watching her waste minutes, Isabel tries to politely send her away, but then something happens and the two of them are locked in the dark inside the store. Can anything else happen to her? Isabel thinks. Yes, she doesn't know, but the most important night of her life has just begun and Marina will play a very important role.