Abigail loves Mondays, and so does the rest of class 305. That’s the day Mr. Caruthers asks them cool questions about history. Today Mr. C asks, “What if Abraham Lincoln never freed the slaves?” Abigail and her friends are ready to plunk their thinking caps on. But this time Mr. C wants them to do more than put their heads together -- he wants them to travel back in time!  Turns out the “What If?” questions are real, and Mr. C has just come back from a visit to the past. He needs their help, because it looks like President Lincoln might quit and never free the slaves! With a time-travel gadget and only two hours to spare, Abigail and her friends are going back to the past. But even though time traveling isn’t hard, convincing Abraham Lincoln not to give up isn’t going to be easy.