What is the name of the book where kids travel back to ancient ireland and see all these mythical creatures?
I think there are two books, but the first one is about these kids who find an old book in a case at their uncle’s house or something, and then on a certain Irish holiday (I don’t remember what it’s called) but they end up in a cave and they somehow time travel back to ancient Ireland and they end up seeing all these different creatures, like a cyclops and a banshee and all sorts of other things. It’s driving me crazy because I can’t find it anywhere and I read it back in middle school.