Whales on Stilts by M.T. Anderson

Imagine that you are Lily Gefelty. She thinks her father has a pretty boring job. But then she spends the day with him at the office. There are so many strange things going on. Her dad just tries to explain them away but Lily isn't buying it. Why is dad's boss wearing a disguise? And what is really going on? Lily and her friends decide they need to find out. She becomes convinced that stilt walking whales are about to take over the world!

The Cannibals by Iain Lawrence

When we last saw young Tom Tin in Lawrence's The Convicts, he was on his way to Australia on a prison ship. His friend Midgely and the other juvenile convicts are also on their way to the prison. But Tom's father is now the captain of the ship and he is determined to find a way to help Tom and Midge out of this situation. But they can't let anyone know that Tom is the captain's son. Midge has come up with an idea based on a book he has read. They will take the longboat off the ship and sail to an island to await Tom's father. Of course, nothing goes as planned and now Tom and Midge are at the mercy of an old convict who they find on the island. Is he also an escapee from justice? Is he really a killer? And are the stories about headhunters and cannibals really true? Join Tom and Midge on a very suspenseful voyage.