It's a rather madcap plot going on. The main five characters are rare breeds of sheep--one raps, one is extremely superficial, one is unusually smart--who find themselves on a quest after a cell phone, thrown from a hot air balloon high overhead, lands on one of them at home in England. They take this event to mean that Lambad, the evil sheep, is threatening Aries, the supreme good sheep who lives in the North, and only with the return of this strange object can the future of all sheep be secured. (See what I mean about ludicrous tendencies?) All of the human characters are somehow involved in strangeness of their own: the men who threw the cell phone are desperate to get it back since data on it can incriminate them in a bank fraud scheme; the sheep's owners just want their sheep back, but when they go to offer a reward they find their life savings have disappeared from the bank (see above); and some other incidental characters think the falling cell phone may have actually been an UFO, and these sheep are now someone being commanded by alien beings. All the humans end up chasing the sheep on their quest, and a good many other strange, improbable, and goofy things happen along the way.
I think this book could do well for engaging young, reluctant male readers. It has enough zaniness to capture their attention and get them invested in the characters, yet it is episodic enough that they won't feel coerced into reading huge chunks at a time if they don't want. I'd suggest this title to just that sort of audience: young reluctant readers and those with an enjoyment for the odd and goofy.