"How do planes fly?"

"How does our fridge work?"

"Can I breathe underwater like a fish?"

Oliver is a curious explorer, so he asks a lot of questions.

Then, one day in the bathtub, he hears a strange gurgle. "What lives down the drain?" he wonders. Soon Oliver is headed down the drain in his homemade submarine on a spectacular mission. But will this clever inventor be able to discover a way back?

In this imaginative and funny adventure story, Judith Rossell introduces a lovable little hero whose curiosity leads him to extraordinary places.