I received this book for free from Reviewer Purchase in exchange for an honest review. This does not affect my opinion of the book or the content of my review.

Josie Byrne's life is spiraling out of control. And just when she thinks it can't get worse, she wakes to an image of herself in the bedroom mirror. Except it's not her at all—the girl in the mirror is blonder and prettier. And her name is Jo.

The two girls are doppelgängers whose universes overlap every twelve hours at 3:59. Fascinated by Jo's perfect world, Josie jumps at the chance to pass through the portal and switch places for a day.

But Jo's world is far from perfect, and the stuff of nightmares lurks around every corner. And when Josie finds herself trapped there, her life becomes more dangerous—and more deadly—than she ever imagined.

Josie’s life seems to be spiraling out of control but things get weird when Josie sees herself or a girl who looks exactly like her in a mirror, it turns out that the girls are doppelgängers. Every 12 hours their universes overlap and Josie thinks that Jo lives a better life than her jumps at the opportunity to switch places for 24 hours. But Jo’s world isn’t as perfect as it seemed and now Josie is trapped there and has to find a way back home. I love books by Gretchen McNeil so I was excited to finally read 3:59, I throughly enjoyed it. We mainly read from Josie’s point of view but at 3:59 we get to see a few things from Jo’s POV as well. There were so many twist and turns that I didn’t know what to expect or who to trust. I liked feeling like I was with Josie on a journey, she had to use everything she knew about physics to figure out how to get back home. I also liked how Josie learned how things may look better on the other side but it’s not always what you think. The people in Jo’s world don’t really trust her so it was hard for Josie to earn their trust and it was interesting to see how everything worked out. I wasn’t expecting most of the things that happened but it just kept me on the edge of my seat. 3:59 is definitely a page turner and I would recommend it!