It is time for the annual family picnic to the beach. And look! Uncle Anton brought a little submarine along for Hank and Hazel to play around with. What will they find at the bottom of the sea? Trouble, no doubt.
In the cellar of their uncle, Hank and Hazel finds a drilling machine that can travel right to the center of the earth. Will they try it out? Will they do something dangerous and stupid in the land of the lava men?
Yes, they will.
In their longest adventure yet, Hank and Hazel tries out a time machine that sends them bouncing through time and space to all the wrong places. They will meet both dinosaurs and robots, and Hank gets to be king. But can they find a way home?