There have been many unique and unlikely animal pairings throughout picture book history. The Owl and the Pussycat, Winnie the Pooh and Piglet, Beatrix Potter’s Dog and Cat storekeepers in The Tale of Ginger and Pickles, and recently, memorably, a fox and a chicken in Beatrice Rodriguez’s The Chicken Thief to name just a few. Added to the list – and perhaps the unlikeliest pairing of them all – is Joan Grant and Neil Curtis’s Cat and Fish.

The quirky charm of this delightful book grabs you right at the very first page and does not let up. Read as either a story of love or friendship, it tells of the immediate attraction and growing affection between the eponymous characters. Cat (the boy) and Fish (girl) elope together and embark on adventures that become increasingly enchanted. Obviously this is a world where normal rules need not apply: The Fish shows a remarkable ability to survive out of water, and likewise the Cat under. The Cat, though plausibly adept at tightrope walking, sneakily does so here while pushing Fish in a wheelbarrow. Both of them make use of a magical boat that variously rows or motors through the night sky, a recurrent backdrop. This is as much a story as it is a dream. Each page is a vignette describing a different location and stage of their affair and like a dream they are scarcely connected consecutively, flitting from the climax of each scene to the next.

The storyline, charming as it is, in the hands of the wrong illustrator would amount to little more than a nice idea, amusing for a while but left behind with the last page. Neil Curtis is not the wrong illustrator. His engraving-style black and white drawings are so fantastic, so striking, that you realise Cat and Fish is an unforgettable experience by about page two. Indeed, the illustrations are so impressive that you find yourself drawing a breath before turning each page, rightly preparing yourself to be impressed; one of those books. Curtis makes Cat and Fish a true joy.

I could go into detail describing my favourite pages, perhaps Cat showing Fish how to climb, Cat floating upon swirling waters while Fish gambols beneath them, or the iconic row-boat in the sky image where they accidentally go ‘up instead of down’, but I would prefer each picture to come as a surprise. Because that is exactly what Cat and Fish does: surprises you. There is no guessing where the story goes, no formula to the tale that allows one to predict what will happen. All you can do is surrender, live in their world for a little while, for it is the world of endless childhood imagination that is only captured rarely, in the very best of picture books. I hold Cat and Fish to be one of these – the very best – because it exhibits in spades the one thing that is shared by all picture book masterpieces: a magical sense that anything is possible.