Twelve-year-old Emily Bennett is the only person in her baseball-obsessed family who doesn't love baseball. She'd rather run track, survive middle school, and avoid the awkward "growing up" talks her mom keeps trying to have.

But when her grandfather gives her an old baseball hat, everything changes.

Suddenly, Emily can hit like a pro. Then the hat disappears.

The next time she sees it, it's in a photograph taken over fifty years ago-on her grandmother's head.

At the same time, Emily starts having vivid dreams that feel a little too real... like she's actually there. In the past.

As friendships shift, secrets surface, and her little sister Nora seems to get all the attention, Emily begins to wonder: is the hat showing her something important-or changing things altogether?

Because if Emily really is slipping into the past, she might have the chance to fix what went wrong...

...but what if changing it makes everything worse?