What if you could go back in time and fix your greatest regret? Would you do it? Should you do it? Sarah Breckton is a grieving mother whose son's school shooting shook their small town to its core. Daniel, the uncle of one of the victims, presents her with the opportunity to change the past. An elixir he has invented for a top-secret project codenamed Mulligan will allow the user's consciousness to travel back to any point in their past to save their future. However, when Sarah agrees to his plan, she finds that fixing the past is more than she bargained for and that Daniel is not all he seems.