We start a look at the great feast of wonderful writing for children that is the Guardian Children's Fiction Prize shortlist by starting with a couple of adventure stories - although neither are quite your traditional adventure stories.
An Island of our Own - Sally Nicholls
After the death of their mother, Holly and Davy are being brought up by their eighteen-year-old brother, Jonathan. They have been struggling to look after themselves and each has had to grow up very fast.
They all put their own needs on hold while their priority becomes the fight to find a way to make ends meet, get everyone to work or school on time, put food on the table and stay together.
You might describe Sally Nicholls 'An Island of Our Own' as starting off with almost a Jacqueline Wilson feel. It makes you believe you are heading for a quite serious family story.
But things quickly change.
It is clever and unexpected that the siblings' journey becomes a road-trip search for treasure and adventure. Their latest quest develops not as one of day to day survival but how to crack codes and travel to the other end of the country.
Jonathan, Holly and Davy get on the trail of clues left by their great-aunt which may lead to buried treasure - and they desperately need that money. And whereas none of them felt they could ask for help before - suddenly all their friends, acquaintances and family (well, most of them) pitch in with helpful suggestions and all sorts of canny ways to find out where their eccentric aunt might have buried her money and get to the next clue.
It's great to see a writer that has the courage to be so unexpected and take the reader in a totally different direction from where you think you are going at the beginning.
The book is a really joyful modern take on an old-fashioned adventure story, but with a really bold and original feel. It can be thoroughly enjoyed as a fabulously warm contemporary road-trip, treasure-hunting adventure - or as a family drama, and will appeal to readers of both.
And probably what is the most satisfying is that by the end of the book it has, indeed, all been about how the siblings are going to cope, cleverly delivering the message that communities can be there to support, but often people don't know how to ask for, or to offer help. While the most fun is had with the mad ways everyone has to try to solve the aunt's cryptic clues.
This has been a big hit with independent booksellers and was voted the winner of the Independent Booksellers Week Children's Fiction Award 2015. It is really great to see that other judges, too, have picked this out as a really outstanding book.
The Lie Tree - Frances Hardinge
In Frances Hardinge's 'The Lie Tree', Faith also finds herself with an unexpected adventure on her hands.
Faith would love to be a scientist and serious, like her father. She rather despises her mother's fripparies and choice of pursuits. But in Victorian times, this is definitely a man's world and Faith may know a lot about science, but she has much to learn about society.
Faith can be more intelligent than most of the people around her and know and learn plenty, but it's a real challenge to be taken seriously, particularly when she becomes convinced her father has been murdered.
But she discovers what women can be good at - manipulating and working behind the scenes and secretly doing things no-one would expect a woman to do. She sets about covertly trying to find out what her father was really working on and who might have guessed his secret.
Without any of her enemies knowing, she gets closer to bringing her father's studies to fruition, while also plotting how to reveal what really happened to her father.
This is a page-turner with a serious heart. It's a thought-provoking and imaginative tale that manages to weave a historical scientific adventure with a thread of feminism and fantasy. Not an easy thing to pull off, but Frances Hardinge does it with lashings of style.
These are both great stories that can be enjoyed by anyone who likes a good mystery - but they both cleverly weave in some serious themes and the layers make them both really enjoyable, very clever, and seriously impressive reads.