Gillian Cross 
Shadow Cat [EPUB ebook] 

An unlikely friendship. An incredible secret. An adventure of a lifetime . . . Nolan leaves school one day to discover that his mum has dyed her hair bright green, sold everything they own, and they’re going on a road trip . . . On the way he meets Feather, the adopted daughter of a famous rock star. This mismatched pair appear to have nothing in common, until they discover an escaped wild cat, a serval, that needs their protection. Together they vow to keep it a secret. But someone else wants the serval too. Someone who will stop at nothing to get their hands on it . . .