Hollow Earth #2: Bone Quill by John and Carole Barrowman

My name is Em. My brother Matt and I are hybrid Animare and Guardians, something never seen before in history. We are able to animate our drawings, and we're also able to use paintings to travel through time. Our mother trapped our father in a painting when we were little, because he wanted to use us to release the beasts from the Hollow Earth. It actually exists! It can only be opened using the bone quill from a black peryton and the Book of Beasts. And my brother and I. There are people still trying to release the monsters, and my mom is missing. I'm not totally sure what's going on, but I think the answers may be found hundreds of years in the past.

You should read book one in the series before this one. Making the father the antagonist is a nice twist, since it creates an emotional conflict for the kids. Matt is impulsive with an attitude, while Em is more logical and makes safe decisions. These character traits create additional conflicts, since the twins travel almost everywhere together. There is a subplot running through the first two books, and this book starts to bring the present and past together. Time travel is always an attention-getter for fans of speculative fiction. I'm still a little bothered about making drawings to escape danger. I mean, there's a beast chasing you or a cave is falling in, but you have time to draw a picture and escape. I still like the overall book!