New Year's Eve 2000. Thirty-six-year-old anesthesiologist Millie is having a bad day. First her pregnant patient's husband turns out to be her ex-boyfriend, then her friends ask her to move out, and at the New Year's Eve party where Millie went in the hope of renewing her relationship with her great university love Joe, it turns out that he has brought a new girlfriend and is going to propose to her. Unable to bear it, Millie takes a second sip from a bottle of tequila given to her the day before and is transported exactly to the moment when she made the first one - to the beginning of the party. The girl decides to use the magic drink to change her fate and get Joe back.