Question about the morning after pill?

So, my friend is about to lose her virginity in a few days. She says she wants it to be all natural, but I talked her into using the morning after pill. But she only bought one. She is going to stay with her boyfriend for over a week. If they have unprotected sex, and she takes the pill after the first time, will it keep her protected throughout the rest of the week if they choose to have unprotected sex again? From my understanding, the morning after pill makes the egg postpone ovulating. So I would think that she would be safe if she only took the one pill as long as it does its job. She will only be there a week. What do you all think? Im not saying its smart or anything, or that I agree with the method. But i just wanna make sure that the pill would protect her throughout the week if it postpones ovulation and she takes it right after the first time having unprotected sex.