Unicorn is back... and he's still grumpy! Unicorn, Narwhal, Mermaid, and Jellyfish are ready for an adventure, and, as Unicorn quite rightly points out, nothing is more adventurous than travelling into SPACE. But when the four friends disagree over which planet to visit first, Unicorn most definitely turns into a very grumpy Grumpycorn and decides to go off on his own. Will Unicorn see the error of his ways? Will he realize that friendship is what makes everything fun? Will he finally stop being such a Grumpycorn? There's only one way to find out... The follow-up to Sarah McIntyre's bestselling Grumpycorn is an imaginative romp celebrating friendship!